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  • 1.
    Abrahamsson, Tobias
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Poxson, David
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Gabrielsson, Erik
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Sandberg, Mats
    RISE Acreo AB, Sweden.
    Simon, Daniel T
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol2019Inngår i: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, artikkel-id 484Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the emerging field of organic bioelectronics, conducting polymers and ion-selective membranes are combined to form resistors, diodes, transistors, and circuits that transport and process both electronic and ionic signals. Such bioelectronics concepts have been explored in delivery devices that translate electronic addressing signals into the transport and dispensing of small charged biomolecules at high specificity and spatiotemporal resolution. Manufacturing such "iontronic" devices generally involves classical thin film processing of polyelectrolyte layers and insulators followed by application of electrolytes. This approach makes miniaturization and integration difficult, simply because the ion selective polyelectrolytes swell after completing the manufacturing. To advance such bioelectronics/iontronics and to enable applications where relatively larger molecules can be delivered, it is important to develop a versatile material system in which the charge/size selectivity can be easily tailormade at the same time enabling easy manufacturing of complex and miniaturized structures. Here, we report a one-pot synthesis approach with minimal amount of organic solvent to achieve cationic hyperbranched polyglycerol films for iontronics applications. The hyperbranched structure allows for tunable pre multi-functionalization, which combines available unsaturated groups used in crosslinking along with ionic groups for electrolytic properties, to achieve a one-step process when applied in devices for monolithic membrane gel formation with selective electrophoretic transport of molecules.

    Fulltekst (pdf)
    fulltext
  • 2.
    Abrikossova, Natalia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Investigation of nanoparticle-cell interactions for development of next generation of biocompatible MRI contrast agents2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Progress in synthesis technologies and advances in fundamental understanding of materials with low dimensionality has led to the birth of a new scientific field, nanoscience, and to strong expectations of multiple applications of nanomaterials. The physical properties of small particles are unique, bridging the gap between atoms and molecules, on one side, and bulk materials on the other side. The work presented in this thesis investigates the potential of using magnetic nanoparticles as the next generation of contrast agents for biomedical imaging. The focus is on gadolinium-based nanoparticles and cellular activity including the uptake, morphology and production of reactive oxygen species.

    Gd ion complexes, like Gd chelates, are used today in the clinic, world-wide. However, there is a need for novel agents, with improved contrast capabilities and increased biocompatibility. One avenue in their design is based on crystalline nanoparticles. It allows to reduce the total number of Gd ions needed for an examination. This can be done by nanotechnology, which allows one to improve and fine tune the physico- chemical properties on the nanomaterial in use, and to increase the number of Gd atoms at a specific site that interact with protons and thereby locally increase the signal. In the present work, synthesis, purification and surface modification of crystalline Gd2O3-based nanoparticles have been performed. The nanoparticles are selected on the basis of their physical properties, that is they show enhanced magnetic properties and therefore may be of high potential interest for applications as contrast agents.

    The main synthesis method of Gd2O3 nanoparticles in this work was the modified “polyol” route, followed by purification of as-synthesized DEG-Gd2O3 nanoparticles suspensions. In most cases the purification step involved dialysis of the nanoparticle samples. In this thesis, organosilane were chosen as an exchange agent for further functionalization. Moreover, several paths have been explored for modification of the nanoparticles, including Tb3+ doping and capping with sorbitol.

    Biocompatibility of the newly designed nanoparticles is a prerequisite for their use in medical applications. Its evaluation is a complex process involving a wide range of biological phenomena. A promising path adopted in this work is to study of nanoparticle interactions with isolated blood cells. In this way one could screen nanomaterial prior to animal studies.

    The primary cell type considered in the thesis are polymorphonuclear neutrophils (PMN) which represent a type of the cells of human blood belonging to the granulocyte family of leukocytes. PMNs act as the first defense of the immune system against invading pathogens, which makes them valuable for studies of biocompatibility of newly synthesized nanoparticles. In addition, an immortalized murine alveolar macrophage cell line (MH-S), THP-1 cell line, and Ba/F3 murine bone marrow-derived cell line were considered to investigate the optimization of the cell uptake and to examine the potential of new intracellular contrast agent for magnetic resonance imaging.

    In paper I, the nanoparticles were investigated in a cellular system, as potential probes for visualization and targeting intended for bioimaging applications. The production of reactive oxygen species (ROS) by means of luminol-dependent chemiluminescence from human neutrophils was studied in presence of Gd2O3 nanoparticles. In paper II, a new design of functionalized ultra-small rare earth-based nanoparticles was reported. The synthesis was done using polyol method followed by PEGylation, and dialysis. Supersmall gadolinium oxide (DEG-Gd2O3) nanoparticles, in the range of 3-5 nm were obtained and carefully characterized. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. In paper III, cell labeling with Gd2O3 nanoparticles in hematopoietic cells was monitored by magnetic resonance imaging (MRI). In paper IV, ultra-small gadolinium oxide nanoparticles doped with terbium ions were synthesized as a potentially bifunctional material with both fluorescent and magnetic contrast agent properties. Paramagnetic behavior was studied. MRI contrast enhancement was received, and the luminescent/ fluorescent property of the particles was attributable to the Tb3+ ion located on the crystal lattice of the Gd2O3 host. Fluorescent labeling of living cells was obtained. In manuscript V, neutrophil granulocytes were investigated with rapid cell signaling communicative processes in time frame of minutes, and their response to cerium-oxide based nanoparticles were monitored using capacitive sensors based on Lab-on-a-chip technology. This showed the potential of label free method used to measure oxidative stress of neutrophil granulocytes. In manuscript VI, investigations of cell-(DEGGd2O3) nanoparticle interactions were carried out. Plain (DEG-Gd2O3) nanoparticles, (DEG-Gd2O3) nanoparticles in presence of sorbitol and (DEG-Gd2O3) nanoparticles capped with sorbitol were studied. Relaxation studies and measurements of the reactive oxygen species production by neutrophils were based on chemiluminescence. Cell morphology was evaluated as a parameter of the nanoparticle induced inflammatory response by means of the fluorescence microscopy.

    The thesis demonstrates high potential of novel Gd2O3-based nanoparticles for development of the next generation contrast agents, that is to find biocompatible compounds with high relaxivity that can be detected at lower doses, and in the future enable targeting to provide great local contrast.

    Delarbeid
    1. Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes
    Åpne denne publikasjonen i ny fane eller vindu >>Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes
    Vise andre…
    2012 (engelsk)Inngår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 23, nr 27, s. 275101-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We have previously shown that gadolinium oxide (Gd2O3) nanoparticles are promising candidates to be used as contrast agents in magnetic resonance (MR) imaging applications. In this study, these nanoparticles were investigated in a cellular system, as possible probes for visualization and targeting intended for bioimaging applications. We evaluated the impact of the presence of Gd2O3 nanoparticles on the production of reactive oxygen species (ROS) from human neutrophils, by means of luminol-dependent chemiluminescence. Three sets of Gd2O3 nanoparticles were studied, i.e. as synthesized, dialyzed and both PEG-functionalized and dialyzed Gd2O3 nanoparticles. In addition, neutrophil morphology was evaluated by fluorescent staining of the actin cytoskeleton and fluorescence microscopy. We show that surface modification of these nanoparticles with polyethylene glycol (PEG) is essential in order to increase their biocompatibility. We observed that the as synthesized nanoparticles markedly decreased the ROS production from neutrophils challenged with prey (opsonized yeast particles) compared to controls without nanoparticles. After functionalization and dialysis, more moderate inhibitory effects were observed at a corresponding concentration of gadolinium. At lower gadolinium concentration the response was similar to that of the control cells. We suggest that the diethylene glycol (DEG) present in the as synthesized nanoparticle preparation is responsible for the inhibitory effects on the neutrophil oxidative burst. Indeed, in the present study we also show that even a low concentration of DEG, 0.3%, severely inhibits neutrophil function. In summary, the low cellular response upon PEG-functionalized Gd2O3 nanoparticle exposure indicates that these nanoparticles are promising candidates for MR-imaging purposes.

    sted, utgiver, år, opplag, sider
    Institute of Physics, 2012
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-79667 (URN)10.1088/0957-4484/23/27/275101 (DOI)000305802000001 ()
    Tilgjengelig fra: 2012-08-14 Laget: 2012-08-13 Sist oppdatert: 2018-11-12
    2. Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement
    Åpne denne publikasjonen i ny fane eller vindu >>Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement
    Vise andre…
    2010 (engelsk)Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, nr 8, s. 5753-5762Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Recently, much attention has been given to the development of biofunctionalized nanoparticles with magnetic properties for novel biomedical imaging. Guided, smart, targeting nanoparticulate magnetic resonance imaging (MRI) contrast agents inducing high MRI signal will be valuable tools for future tissue specific imaging and investigation of molecular and cellular events. In this study, we report a new design of functionalized ultrasmall rare earth based nanoparticles to be used as a positive contrast agent in MRI. The relaxivity is compared to commercially available Gd based chelates. The synthesis, PEGylation, and dialysis of small (3−5 nm) gadolinium oxide (DEG-Gd2O3) nanoparticles are presented. The chemical and physical properties of the nanomaterial were investigated with Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and dynamic light scattering. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. The proton relaxation times as a function of dialysis time and functionalization were measured at 1.5 T. A capping procedure introducing stabilizing properties was designed and verified, and the dialysis effects were evaluated. A higher proton relaxivity was obtained for as-synthesized diethylene glycol (DEG)-Gd2O3 nanoparticles compared to commercial Gd-DTPA. A slight decrease of the relaxivity for as-synthesized DEG-Gd2O3 nanoparticles as a function of dialysis time was observed. The results for functionalized nanoparticles showed a considerable relaxivity increase for particles dialyzed extensively with r1 and r2 values approximately 4 times the corresponding values for Gd-DTPA. The microscopy study showed that PEGylated nanoparticles do not activate neutrophils in contrast to uncapped Gd2O3. Finally, the nanoparticles are equipped with Rhodamine to show that our PEGylated nanoparticles are available for further coupling chemistry, and thus prepared for targeting purposes. The long term goal is to design a powerful, directed contrast agent for MRI examinations with specific targeting possibilities and with properties inducing local contrast, that is, an extremely high MR signal at the cellular and molecular level.

    sted, utgiver, år, opplag, sider
    American Chemical Society (ACS), 2010
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-54946 (URN)10.1021/la903566y (DOI)000276562300061 ()
    Tilgjengelig fra: 2010-04-23 Laget: 2010-04-23 Sist oppdatert: 2018-10-29bibliografisk kontrollert
    3. Gd2O3 nanoparticles in hematopoietic cells for MRI contrast enhancement
    Åpne denne publikasjonen i ny fane eller vindu >>Gd2O3 nanoparticles in hematopoietic cells for MRI contrast enhancement
    Vise andre…
    2011 (engelsk)Inngår i: International journal of nano medicine, ISSN 1178-2013, Vol. 6, s. 3233-3240Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    As the utility of magnetic resonance imaging (MRI) broadens, the importance of having specific and efficient contrast agents increases and in recent time there has been a huge development in the fields of molecular imaging and intracellular markers. Previous studies have shown that gadolinium oxide (Gd2O3) nanoparticles generate higher relaxivity than currently available Gd chelates: In addition, the Gd2O3 nanoparticles have promising properties for MRI cell tracking. The aim of the present work was to study cell labeling with Gd2O3 nanoparticles in hematopoietic cells and to improve techniques for monitoring hematopoietic stem cell migration by MRI. Particle uptake was studied in two cell lines: the hematopoietic progenitor cell line Ba/F3 and the monocytic cell line THP-1. Cells were incubated with Gd2O3 nanoparticles and it was investigated whether the transfection agent protamine sulfate increased the particle uptake. Treated cells were examined by electron microscopy and MRI, and analyzed for particle content by inductively coupled plasma sector field mass spectrometry. Results showed that particles were intracellular, however, sparsely in Ba/F3. The relaxation times were shortened with increasing particle concentration. Relaxivities, r1 and r2 at 1.5 T and 21°C, for Gd2O3 nanoparticles in different cell samples were 3.6–5.3 s-1 mM-1 and 9.6–17.2 s-1 mM-1, respectively. Protamine sulfate treatment increased the uptake in both Ba/F3 cells and THP-1 cells. However, the increased uptake did not increase the relaxation rate for THP-1 as for Ba/F3, probably due to aggregation and/or saturation effects. Viability of treated cells was not significantly decreased and thus, it was concluded that the use of Gd2O3 nanoparticles is suitable for this type of cell labeling by means of detecting and monitoring hematopoietic cells. In conclusion, Gd2O3 nanoparticles are a promising material to achieve positive intracellular MRI contrast; however, further particle development needs to be performed.

    sted, utgiver, år, opplag, sider
    Manchester, UK: Dove Medical Press Ltd, 2011
    Emneord
    gadolinium oxide, magnetic resonance imaging, contrast agent, cell labeling, Ba/F3 cells, THP-1 cells
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-72275 (URN)10.2147/IJN.S23940 (DOI)000298164300001 ()
    Merknad

    funding agencies|Swedish Research Council| 621-2007-3810 621-2009-5148 521-2009-3423 |VINNOVA| 2009-00194 |Center in Nanoscience and Technology at LiTH (CeNano)||

    Tilgjengelig fra: 2011-11-24 Laget: 2011-11-24 Sist oppdatert: 2018-10-29
    4. Synthesis and Characterization of Tb3+-Doped Gd2O3 Nanocrystals: A Bifunctional Material with Combined Fluorescent Labeling and MRI Contrast Agent Properties
    Åpne denne publikasjonen i ny fane eller vindu >>Synthesis and Characterization of Tb3+-Doped Gd2O3 Nanocrystals: A Bifunctional Material with Combined Fluorescent Labeling and MRI Contrast Agent Properties
    Vise andre…
    2009 (engelsk)Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, nr 17, s. 6913-6920Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Ultrasmall gadolinium oxide nanoparticles doped with terbium ions were synthesized by the polyol route and characterized as a potentially bifunctional material with both fluorescent and magnetic contrast agent properties. The structural, optical, and magnetic properties of the organic-acid-capped and PEGylated Gd2O3:Tb3+ nanocrystals were studied by HR-TEM, XPS, EDX, IR, PL, and SQUID. The luminescent/fluorescent property of the particles is attributable to the Tb3+ ion located on the crystal lattice of the Gd2O3 host. The paramagnetic behavior of the particles is discussed. Pilot studies investigating the capability of the nanoparticles for fluorescent labeling of living cells and as a MRI contrast agent were also performed. Cells of two cell lines (THP-1 cells and fibroblasts) were incubated with the particles, and intracellular particle distribution was visualized by confocal microscopy. The MRI relaxivity of the PEGylated nanoparticles in water at low Gd concentration was assessed showing a higher T-1 relaxation rate compared to conventional Gd-DTPA chelates and comparable to that of undoped Gd2O3 nanoparticles.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-12944 (URN)10.1021/jp808708m (DOI)000265529700009 ()
    Merknad

    On the day of the defence date the status of this article was Submitted

    Tilgjengelig fra: 2008-02-21 Laget: 2008-02-21 Sist oppdatert: 2018-10-29bibliografisk kontrollert
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  • 3. Bestill onlineKjøp publikasjonen >>
    Adam, Rania Elhadi
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Synthesis and Characterization of Some Nanostructured Materials for Visible Light-driven Photo Processes2020Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Nanostructured materials for visible light driven photo-processes such as photodegradation of organic pollutants and photoelectrochemical (PEC) water oxidation for hydrogen production are very attractive because of the positive impact on the environment. Metal oxides-based nanostructures are widely used in these photoprocesses due to their unique properties. But single nanostructured metal oxide material might suffer from low efficiency and instability in aqueous solutions under visible light. These facts make it important to have an efficient and reliable nanocomposite for the photo-processes. The combination of different nanomaterials to form a composite configuration can produce a material with new properties. The new properties which are due to the synergetic effect, are a combination of the properties of all the counterparts of the nanocomposite. Zinc oxides (ZnO) have unique optical and electrical properties which grant it to be used in optoelectronics, sensors, solar cells, nanogenerators, and photocatalysis activities. Although ZnO absorbs visible light from the sun due to the deep level band, it mainly absorbs ultraviolet wavelengths which constitute a small portion of the whole solar spectrum range. Also, ZnO has a problem with the high recombination rate of the photogenerated electrons. These problems might reduce its applicability to the photo-process. Therefore, our aim is to develop and investigate different nanocomposites materials based on the ZnO nanostructures for the enhancement of photocatalysis processes using the visible solar light as a green source of energy. Two photo-processes were applied to examine the developed nanocomposites through photocatalysis: (1) the photodegradation of organic dyes, (2) PEC water splitting. In the first photo-process, we used the ZnO nanoparticles (NPs), Magnesium (Mg)-doped ZnO NPs, and plasmonic ZnO/graphene-based nanocomposite for the decomposition of some organic dyes that have been used in industries. For the second photo-process, ZnO photoelectrode composite with different silver-based semiconductors to enhance the performance of the ZnO photoelectrode was used for PEC reaction analysis to perform water splitting. The characterization and photocatalysis experiment results showed remarkable enhancement in the photocatalysis efficiency of the synthesized nanocomposites. The observed improved properties of the ZnO are due to the synergetic effects are caused by the addition of the other nanomaterials. Hence, the present thesis attends to the synthesis and characterization of some nanostructured materials composite with ZnO that are promising candidates for visible light-driven photo-processes.  

    Delarbeid
    1. Synthesis of ZnO nanoparticles by co-precipitation method for solar driven photodegradation of Congo red dye at different pH
    Åpne denne publikasjonen i ny fane eller vindu >>Synthesis of ZnO nanoparticles by co-precipitation method for solar driven photodegradation of Congo red dye at different pH
    2018 (engelsk)Inngår i: PHOTONICS AND NANOSTRUCTURES-FUNDAMENTALS AND APPLICATIONS, ISSN 1569-4410, Vol. 32, s. 11-18Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Solar driven photocatalytic processes to remove organic pollutants from wastewater and other aqueous solutions is very important and useful due to its environmental benefits regarding sustainability aspect. In this article, we report a study on the use of bare zinc oxide (ZnO) nanoparticles (NPs) prepared by the chemical low temperature co-precipitation method and used as a catalyst to degrade the Congo red dye from aqueous solution using solar radiation. We performed the photocatalytic experiments for degradation of Congo red dye under solar radiation at different pH values. The results showed that the ZnO NPs are effective under solar radiation for degradation of Congo red dye. Even when the pH was varied down to 4 or raised to 10, the degradation was observed to be slightly improved. This result is due to the excess of radicals species, which enhance the photocatalytic process. In general, the observed degradation efficiency of the ZnO NPs is due to the deep level defects within the band gap that were introduced during the growth process of the ZnO NPs, which enhance the absorption wavelength band towards the visible light region. Recycling of the ZnO NPs for 3 successive runs have indicated the feasibility of reusing the NPs for several times. This implies that by using bare ZnO NPs an efficient approach for degradation of toxic waste can be achieved. Radical scavengers were used to evaluate the role of the radicals in the reaction mechanism.

    sted, utgiver, år, opplag, sider
    ELSEVIER SCIENCE BV, 2018
    Emneord
    ZnO nanoparticles; Point defects; Photocatalytic
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-153525 (URN)10.1016/j.photonics.2018.08.005 (DOI)000451653700003 ()
    Merknad

    Funding Agencies|department of Science and Technology, Linkoping University, Sweden

    Tilgjengelig fra: 2018-12-20 Laget: 2018-12-20 Sist oppdatert: 2020-03-18
    2. Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light
    Åpne denne publikasjonen i ny fane eller vindu >>Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light
    Vise andre…
    2020 (engelsk)Inngår i: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 99, artikkel-id 106053Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Doped semiconductors nanostructures (NSs) have shown great interest as a potential for green and efficient photocatalysis activities. Magnesium (Mg)-doped zinc oxide (ZnO) nanoparticles (NPs) has been synthesized by a one-step chemical low temperature (60 °C) co-precipitation method without further calcination and their photocatalytic performance for photodegradation of Methylene blue (MB) dye under the illumination of solar light is investigated. The crystal structure of the synthesized NPs is examined by X-ray diffraction (XRD). XRD data indicates a slight shift towards higher 2θ angle in Mg-doped samples as compared to the pure ZnO NPs which suggest the incorporation of Mg2+ into ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS), UV–Vis spectrophotometer and cathodoluminescence (CL) spectroscopy, were used to study electronics, and optical properties, respectively. The XPS analysis confirms the substitution of the Zn2+ by the Mg2+ into the ZnO crystal lattice in agreement with the XRD data. The photocatalytic activities showed a significant enhancement of the Mg-doped ZnO NPs in comparison with pure ZnO NPs. Hole/radical scavengers were used to reveal the mechanism of the photodegradation. It was found that the addition of the Mg to the ZnO lattices increases the absorption of the hydroxyl ions at the surface of the NPs and hence acts as a trap site leading to decrease the electron-hole pair and consequently enhancing the photodegradation.

    sted, utgiver, år, opplag, sider
    Elsevier, 2020
    Emneord
    ZnO nanoparticles, Mg-doped ZnO NPs, Photocatalytic, Photodegradation, Methylene blue, Congo red
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-164333 (URN)10.1016/j.solidstatesciences.2019.106053 (DOI)000516720100024 ()2-s2.0-85074706430 (Scopus ID)
    Tilgjengelig fra: 2020-03-18 Laget: 2020-03-18 Sist oppdatert: 2020-03-24bibliografisk kontrollert
    3. Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities
    Åpne denne publikasjonen i ny fane eller vindu >>Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities
    Vise andre…
    2019 (engelsk)Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, nr 52, s. 30585-30598Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    High-efficiency photocatalysts are crucial for the removal of organic pollutants and environmental sustainability. In the present work, we report on a new low-temperature hydrothermal chemical method, assisted by ultrasonication, to synthesize disruptive plasmonic ZnO/graphene/Ag/AgI nanocomposites for solar-driven photocatalysis. The plasmonic nanocomposites were investigated by a wide range of characterization techniques, confirming successful formation of photocatalysts with excellent degradation efficiency. Using Congo red as a model dye molecule, our experimental results demonstrated a photocatalytic reactivity exceeding 90% efficiency after one hour simulated solar irradiation. The significantly enhanced degradation efficiency is attributed to improved electronic properties of the nanocomposites by hybridization of the graphene and to the addition of Ag/AgI which generates a strong surface plasmon resonance effect in the metallic silver further improving the photocatalytic activity and stability under solar irradiation. Scavenger experiments suggest that superoxide and hydroxyl radicals are responsible for the photodegradation of Congo red. Our findings are important for the fundamental understanding of the photocatalytic mechanism of ZnO/graphene/Ag/AgI nanocomposites and can lead to further development of novel efficient photocatalyst materials.

    sted, utgiver, år, opplag, sider
    Royal Meteorological Society, 2019
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-160568 (URN)10.1039/C9RA06273D (DOI)000487989300064 ()
    Merknad

    Funding agencies: Department of Science and Technology (ITN) at Campus Norrkoping, Linkoping University, Sweden; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation

    Tilgjengelig fra: 2019-09-30 Laget: 2019-09-30 Sist oppdatert: 2020-03-18bibliografisk kontrollert
    4. n–n ZnO–Ag2CrO4 heterojunction photoelectrodes with enhanced visible-light photoelectrochemical properties
    Åpne denne publikasjonen i ny fane eller vindu >>n–n ZnO–Ag2CrO4 heterojunction photoelectrodes with enhanced visible-light photoelectrochemical properties
    Vise andre…
    2019 (engelsk)Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, nr 14, s. 7992-8001Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this study, ZnO nanorods (NRs) were hydrothermally grown on an Au-coated glass substrate at a relatively low temperature (90 °C), followed by the deposition of Ag2CrO4 particles via a successive ionic layer adsorption and reaction (SILAR) route. The content of the Ag2CrO4 particles on ZnO NRs was controlled by changing the number of SILAR cycles. The fabricated ZnO–Ag2CrO4 heterojunction photoelectrodes were subjected to morphological, structural, compositional, and optical property analyses; their photoelectrochemical (PEC) properties were investigated under simulated solar light illumination. The photocurrent responses confirmed that the ability of the ZnO–Ag2CrO4 heterojunction photoelectrodes to separate the photo-generated electron–hole pairs is stronger than that of bare ZnO NRs. Impressively, the maximum photocurrent density of about 2.51 mA cm−2 at 1.23 V (vs. Ag/AgCl) was measured for the prepared ZnO–Ag2CrO4 photoelectrode with 8 SILAR cycles (denoted as ZnO–Ag2CrO4-8), which exhibited about 3-fold photo-enhancement in the current density as compared to bare ZnO NRs (0.87 mA cm−2) under similar conditions. The improvement in photoactivity was attributed to the ideal band gap and high absorption coefficient of the Ag2CrO4 particles, which resulted in improved solar light absorption properties. Furthermore, an appropriate annealing treatment was proven to be an efficient process to increase the crystallinity of Ag2CrO4 particles deposited on ZnO NRs, which improved the charge transport characteristics of the ZnO–Ag2CrO4-8 photoelectrode annealed at 200 °C and increased the performance of the photoelectrode. The results achieved in the present work present new insights for designing n–n heterojunction photoelectrodes for efficient and cost-effective PEC applications and solar-to-fuel energ

    sted, utgiver, år, opplag, sider
    Royal Society of Chemistry, 2019
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-155657 (URN)10.1039/C9RA00639G (DOI)000462646000051 ()2-s2.0-85062919263 (Scopus ID)
    Merknad

    Funding agencies: University of Mohaghegh Ardabili-Iran and Linkoping University-Sweden; AForsk [17-457

    Tilgjengelig fra: 2019-03-22 Laget: 2019-03-22 Sist oppdatert: 2020-03-18bibliografisk kontrollert
    5. ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation
    Åpne denne publikasjonen i ny fane eller vindu >>ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation
    Vise andre…
    2019 (engelsk)Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, nr 15, s. 8271-8279Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Ag-based compounds are excellent co-catalyst that can enhance harvesting visible light and increase photo-generated charge carrier separation owing to its surface plasmon resonance (SPR) effect in photoelectrochemical (PEC) applications. However, the PEC performance of a ZnO/Ag/Ag2WO4 heterostructure with SPR behavior has not been fully studied so far. Here we report the preparation of a ZnO/Ag/Ag2WO4 photo-electrode with SPR behavior by a low temperature hydrothermal chemical growth method followed by a successive ionic layer adsorption and reaction (SILAR) method. The properties of the prepared samples were investigated by different characterization techniques, which confirm that Ag/Ag2WO4 was deposited on the ZnO NRs. The Ag2WO4/Ag/ZnO photo-electrode showed an enhancement in PEC performance compared to bare ZnO NRs. The observed enhancement is attributed to the red shift of the optical absorption spectrum of the Ag2WO4/Ag/ZnO to the visible region (>400 nm) and to the SPR effect of surface metallic silver (Ag0) particles from the Ag/Ag2WO4 that could generate electron–hole pairs under illumination of low energy visible sun light. Finally, we proposed the PEC mechanism of the Ag2WO4/Ag/ZnO photo-electrode with an energy band structure and possible electron–hole separation and transportation in the ZnO/Ag/Ag2WO4 heterostructure with SPR effect for water oxidation. ER

    sted, utgiver, år, opplag, sider
    Royal Society of Chemistry, 2019
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-155655 (URN)10.1039/C8RA10141H (DOI)000461445300016 ()
    Tilgjengelig fra: 2019-03-22 Laget: 2019-03-22 Sist oppdatert: 2020-03-18bibliografisk kontrollert
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  • 4.
    Adam, Rania Elhadi
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Alnoor, Hatim
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Pozina, Galia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Liu, Xianjie
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Willander, Magnus
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik.
    Nur, Omer
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik.
    Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light2020Inngår i: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 99, artikkel-id 106053Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Doped semiconductors nanostructures (NSs) have shown great interest as a potential for green and efficient photocatalysis activities. Magnesium (Mg)-doped zinc oxide (ZnO) nanoparticles (NPs) has been synthesized by a one-step chemical low temperature (60 °C) co-precipitation method without further calcination and their photocatalytic performance for photodegradation of Methylene blue (MB) dye under the illumination of solar light is investigated. The crystal structure of the synthesized NPs is examined by X-ray diffraction (XRD). XRD data indicates a slight shift towards higher 2θ angle in Mg-doped samples as compared to the pure ZnO NPs which suggest the incorporation of Mg2+ into ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS), UV–Vis spectrophotometer and cathodoluminescence (CL) spectroscopy, were used to study electronics, and optical properties, respectively. The XPS analysis confirms the substitution of the Zn2+ by the Mg2+ into the ZnO crystal lattice in agreement with the XRD data. The photocatalytic activities showed a significant enhancement of the Mg-doped ZnO NPs in comparison with pure ZnO NPs. Hole/radical scavengers were used to reveal the mechanism of the photodegradation. It was found that the addition of the Mg to the ZnO lattices increases the absorption of the hydroxyl ions at the surface of the NPs and hence acts as a trap site leading to decrease the electron-hole pair and consequently enhancing the photodegradation.

  • 5.
    Aftab, Umair
    et al.
    Mehran Univ Engn and Technol, Pakistan.
    Tahira, Aneela
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Mazzaro, Raffaello
    Italian Natl Res Council, Italy.
    Abro, Muhammad Ishaq
    Mehran Univ Engn and Technol, Pakistan.
    Baloch, Muhammad Moazam
    Mehran Univ Engn and Technol, Pakistan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Yu, Cong
    Chinese Acad Sci, Peoples R China.
    Ibupoto, Zafar Hussain
    Univ Sindh, Pakistan.
    The chemically reduced CuO-Co3O4 composite as a highly efficient electrocatalyst for oxygen evolution reaction in alkaline media2019Inngår i: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 9, nr 22, s. 6274-6284Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The fabrication of efficient, alkaline-stable and nonprecious electrocatalysts for the oxygen evolution reaction is highly needed; however, it is a challenging task. Herein, we report a noble metal-free advanced catalyst, i.e. the chemically reduced mixed transition metal oxide CuO-Co3O4 composite, with outstanding oxygen evolution reaction activity in alkaline media. Sodium borohydride (NaBH4) was used as a reducing agent for the mixed transition metal oxide CuO-Co3O4. The chemically reduced composite carried mixed valence states of Cu and Co, which played a dynamic role in driving an excellent oxygen evolution reaction process. The X-ray photo-electron spectroscopy (XPS) study confirmed high density of active sites in the treated sample with a large number of oxygen vacancies. The developed electrocatalyst showed the lowest overpotential of 144.5 mV vs. the reversible hydrogen electrode (RHE) to achieve the current density of 40 mA cm(-2) and remained stable for 40 hours throughout the chronoamperometry test at the constant potential of 1.39 V vs. RHE. Moreover, the chemically reduced composite was highly durable. Electrochemical impedance spectroscopy (EIS) confirmed the low charge transfer resistance of 13.53 ohms for the chemically reduced composite, which was 50 and 26 times smaller than that of Co3O4 and untreated CuO-Co3O4, respectively. The electrochemically active surface area for the chemically reduced composite was found to be greater than that for pristine CuO, Co3O4 and untreated pristine CuO-Co3O4. These findings reveal the possibility of a new gateway for the capitalization of a chemically reduced sample into diverse energy storage and conversion systems such as lithium-ion batteries and supercapacitors.

  • 6.
    Ahmadkhaniha, D.
    et al.
    Jonkoping Univ, Sweden.
    Eriksson, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Leisner, P.
    Jonkoping Univ, Sweden; RISE Res Inst Sweden, Sweden.
    Zanella, C.
    Jonkoping Univ, Sweden.
    Effect of SiC particle size and heat-treatment on microhardness and corrosion resistance of NiP electrodeposited coatings2018Inngår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 769, s. 1080-1087Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrodeposition of NiP composite coatings with nano and sub-micron sized SiC has been carried out to investigate the possibility of replacing hard chromium coatings. The composition and structure of the coatings were evaluated by energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis, respectively. Microhardness was measured by Vickers indentation and polarization measurements were carried out to study the corrosion behavior of the coatings. The results showed that submicron particles can be codeposited with a higher content as compared to nano sized ones. However, even if a smaller amount of the nano-sized SiC particles are incorporated in the coating, the contribution to an increasing microhardness was comparable with the submicron sized particles, which can be related to the higher density of codeposited particles. SiC particles did not change the anodic polarization behavior of NiP coatings in a 3.5% NaCl solution. Finally, the effect of heat-treatment on the coatings properties at 400 degrees C for 1 h was studied to investigate the contribution of particles and heat-treatment on hardness and corrosion properties. It was found that the heat-treatment doubled the microhardness and changed the anodic polarization behavior of the coatings from passive to active with respect to the asplated conditions. (C) 2018 Elsevier B.V. All rights reserved.

  • 7.
    Ahsan, Aisha
    et al.
    Univ Basel, Switzerland.
    Mousavi, S. Fatemeh
    Univ Basel, Switzerland.
    Nijs, Thomas
    Univ Basel, Switzerland.
    Nowakowska, Sylwia
    Univ Basel, Switzerland.
    Popova, Olha
    Univ Basel, Switzerland.
    Wackerlin, Aneliia
    Univ Basel, Switzerland.
    Björk, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Gade, Lutz H.
    Heidelberg Univ, Germany.
    Jung, Thomas A.
    Univ Basel, Switzerland; Paul Scherrer Inst, Switzerland.
    Watching nanostructure growth: kinetically controlled diffusion and condensation of Xe in a surface metal organic network2019Inngår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, nr 11, s. 4895-4903Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Diffusion, nucleation and growth provide the fundamental access to control nanostructure growth. In this study, the temperature activated diffusion of Xe at and between different compartments of an on-surface metal organic coordination network on Cu(111) has been visualized in real space. Xe atoms adsorbed at lower energy sites become mobile with increased temperature and gradually populate energetically more favourable binding sites or remain in a delocalized fluid form confined to diffusion along a topological subset of the on-surface network. These diffusion pathways can be studied individually under kinetic control via the chosen thermal energy kT of the sample and are determined by the network and sample architecture. The spatial distribution of Xe in its different modes of mobility and the time scales of the motion is revealed by Scanning Tunneling Microscopy (STM) at variable temperatures up to 40 K and subsequent cooling to 4 K. The system provides insight into the diffusion of a van der Waals gas on a complex structured surface and its nucleation and coarsening/growth into larger condensates at elevated temperature under thermodynamic conditions.

  • 8.
    Aijaz, Asim
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan. Uppsala University, Sweden.
    Louring, Sascha
    Aarhus University, Denmark; Danish Technology Institute, Denmark.
    Lundin, Daniel
    University of Paris Saclay, France.
    Kubart, Tomas
    Uppsala University, Sweden.
    Jensen, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Sarakinos, Kostas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Synthesis of hydrogenated diamondlike carbon thin films using neon-acetylene based high power impulse magnetron sputtering discharges2016Inngår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 34, nr 6, artikkel-id 061504Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydrogenated diamondlike carbon (DLC:H) thin films exhibit many interesting properties that can be tailored by controlling the composition and energy of the vapor fluxes used for their synthesis. This control can be facilitated by high electron density and/or high electron temperature plasmas that allow one to effectively tune the gas and surface chemistry during film growth, as well as the degree of ionization of the film forming species. The authors have recently demonstrated by adding Ne in an Ar-C high power impulse magnetron sputtering (HiPIMS) discharge that electron temperatures can be effectively increased to substantially ionize C species [Aijaz et al., Diamond Relat. Mater. 23, 1 (2012)]. The authors also developed an Ar-C2H2 HiPIMS process in which the high electron densities provided by the HiPIMS operation mode enhance gas phase dissociation reactions enabling control of the plasma and growth chemistry [Aijaz et al., Diamond Relat. Mater. 44, 117 (2014)]. Seeking to further enhance electron temperature and thereby promote electron impact induced interactions, control plasma chemical reaction pathways, and tune the resulting film properties, in this work, the authors synthesize DLC: H thin films by admixing Ne in a HiPIMS based Ar/C2H2 discharge. The authors investigate the plasma properties and discharge characteristics by measuring electron energy distributions as well as by studying discharge current characteristics showing an electron temperature enhancement in C2H2 based discharges and the role of ionic contribution to the film growth. These discharge conditions allow for the growth of thick (amp;gt;1 mu m) DLC: H thin films exhibiting low compressive stresses (similar to 0.5 GPa), high hardness (similar to 25 GPa), low H content (similar to 11%), and density in the order of 2.2 g/cm(3). The authors also show that film densification and change of mechanical properties are related to H removal by ion bombardment rather than subplantation. (C) 2016 American Vacuum Society.

    Fulltekst (pdf)
    fulltext
  • 9.
    Ail, Ujwala
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Ullah Khan, Zia
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Granberg, Hjalmar
    Innventia AB, Sweden.
    Berthold, Fredrik
    Innventia AB, Sweden.
    Parasuraman, Rajasekar
    Mat Research Centre, India.
    Urnarji, Arun M.
    Mat Research Centre, India.
    Slettengren, Kerstin
    Innventia AB, Sweden.
    Pettersson, Henrik
    Innventia AB, Sweden.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Room temperature synthesis of transition metal silicide-conducting polymer micro-composites for thermoelectric applications2017Inngår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 225, s. 55-63Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Organic polymer thermoelectrics (TE) as well as transition metal (TM) silicides are two thermoelectric class of materials of interest because they are composed of atomic elements of high abundatice; which is a prerequisite for mass implementation of thermoelectric (TE) solutions for solar and waste heat recovery. But both materials have drawbacks when it comes to finding low-cost manufacturing. The metal silicide needs high temperature (amp;gt;1000 degrees C) for creating TE legs in a device from solid powder, but it is easy to achieve long TE legs in this case. On the contrary, organic TEs are synthesized at low temperature from solution. However, it is difficult to form long legs or thick films because of their low solubility. In this work, we propose a novel method for the room temperature synthesis of TE composite containing the microparticles of chromium disilicide; CrSi2 (inorganic filler) in an organic matrix of nanofibrillated cellulose-poly(3,4-ethyelenedioxythiophene)-polystyrene sulfonate (NFC-PEDOT:PSS). With this method, it is easy to create long TE legs in a room temperature process. The originality of the approach is the use of conducting polymer aerogel microparticles mixed with CrSi2 microparticles to obtain a composite solid at room temperature under pressure. We foresee that the method can be scaled up to fabricate and pattern TE modules. The composite has an electrical conductivity (sigma) of 5.4 +/- 0.5 S/cm and the Seebeck coefficient (a) of 88 +/- 9 mu V/K, power factor (alpha(2)sigma) of 4 +/- 1 mu Wm(-1) K-2 at room temperature. At a temperature difference of 32 degrees C, the output power/unit area drawn across the load, with the resistance same as the internal resistance of the device is 0.6 +/- 0.1 mu W/cm(2). (C) 2017 Elsevier B.V. All rights reserved.

    Fulltekst (pdf)
    fulltext
  • 10.
    Ajjan, Fátima
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Javad Jafari, Mohammad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Rebis, T.
    Poznan University of Tech, Poland.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Spectroelectrochemical investigation of redox states in a polypyrrole/lignin composite electrode material2015Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, nr 24, s. 12927-12937Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report spectroelectrochemical studies to investigate the charge storage mechanism of composite polypyrrole/lignin electrodes. Renewable bioorganic electrode materials were produced by electropolymerization of pyrrole in the presence of a water-soluble lignin derivative acting as a dopant. The resulting composite exhibited enhanced charge storage abilities due to a lignin-based faradaic process, which was expressed after repeated electrochemical redox of the material. The in situ FTIR spectroelectrochemistry results show the formation of quinone groups, and reversible oxidation-reduction of these groups during charge-discharge experiments in the electrode materials. The most significant IR bands include carbonyl absorption near 1705 cm(-1), which is attributed to the creation of quinone moieties during oxidation, and absorption at 1045 cm(-1) which is due to hydroquinone moieties.

  • 11.
    Ajjan Godoy, Fátima Nadia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Biohybrid Polymer Electrodes for Renewable Energy Storage2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Daily and seasonally fluctuating energy supply and demand requires adequate energy storage solutions. In recent years electrochemical supercapacitors have attracted considerable attention due to their ability to both store and deliver electrical energy efficiently. Our efforts are focused on developing and optimizing sustainable organic electrode materials for supercapacitors based on renewable bioorganic materials, offering a cheap, environmentally friendly and scalable alternative to store energy. In particular, we are using the second most abundant biopolymer in nature, lignin (Lig), which is an insulating material. However, when used in combination with electroactive and conducting polymers such as polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT), the biohybrid electrodes PPy/Lig and PEDOT/Lig display significantly enhanced energy storage performance as compared to the pristine conducting polymers without the lignin. Redox cyclic voltammetry and galvanostatic charge/discharge measurements indicate that the enhanced performance is due to the additional pseudocapacitance generated by the quinone moieties in lignin. Moreover, a conjugated redoxpolymer poly(aminoanthraquinone) PAAQ, with intrinsic quinone functions and excellentstability, has been combined with lignin and PEDOT resulting in a trihybrid bioelectrode. PEDOT compensates the low conductivity of PAAQ and provides electrical pathways to the quinone groups. The electrochemically generated quinones undergo a two electron, two protonredox process within the biohybrid electrodes as revealed by FTIR spectroelectrochemistry.These remarkable features reveal the exciting potential of a full organic energy storage device with long cycle life. Therefore, supercapacitor devices were designed in symmetric or asymmetric two electrode configuration. The best electrochemical performance was achieved by the asymmetric supercapacitor based on PEDOT+Lignin/PAAQ as the positive electrode and PEDOT/PAAQ as the negative electrode. This device exhibits superior electrochemical performance and outstanding stability after 10000 charge/discharge cycles due to the synergistic effect of the two electrodes. Finally, we have characterized the response of this supercapacitor device when charged with the intermittent power supply from an organic photovoltaic module. We have designed charging/discharging conditions such that reserve power was available in the storage device at all times. This work has resulted in an inexpensive fully organic system witht he dual function of energy conversion and storage.

    Delarbeid
    1. Biopolymer hybrid electrodes for scalable electricity storage
    Åpne denne publikasjonen i ny fane eller vindu >>Biopolymer hybrid electrodes for scalable electricity storage
    2016 (engelsk)Inngår i: Materials Horizons, ISSN 2051-6347, E-ISSN 2051-6355, Vol. 3, nr 3, s. 174-185Artikkel, forskningsoversikt (Fagfellevurdert) Published
    Abstract [en]

    Powering the future, while maintaining a cleaner environment and a strong socioeconomic growth, is going to be one of the biggest challenges faced by mankind in the 21st century. The first step in overcoming the challenge for a sustainable future is to use energy more efficiently so that the demand for fossil fuels can be reduced drastically. The second step is a transition from the use of fossil fuels to renewable energy sources. In this sense, organic electrode materials are becoming increasingly attractive compared to inorganic electrode materials which have reached a plateau regarding performance and have severe drawbacks in terms of cost, safety and environmental friendliness. Using organic composites based on conducting polymers, such as polypyrrole, and abundant, cheap and naturally occurring biopolymers rich in quinones, such as lignin, has recently emerged as an interesting alternative. These materials, which exhibit electronic and ionic conductivity, provide challenging opportunities in the development of new charge storage materials. This review presents an overview of recent developments in organic biopolymer composite electrodes as renewable electroactive materials towards sustainable, cheap and scalable energy storage devices.

    sted, utgiver, år, opplag, sider
    ROYAL SOC CHEMISTRY, 2016
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-128741 (URN)10.1039/c5mh00261c (DOI)000375296600002 ()
    Merknad

    Funding Agencies|Knut and Alice Wallenberg Foundation; Wallenberg Scholar grant

    Tilgjengelig fra: 2016-05-31 Laget: 2016-05-30 Sist oppdatert: 2017-11-30
    2. Spectroelectrochemical investigation of redox states in a polypyrrole/lignin composite electrode material
    Åpne denne publikasjonen i ny fane eller vindu >>Spectroelectrochemical investigation of redox states in a polypyrrole/lignin composite electrode material
    Vise andre…
    2015 (engelsk)Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, nr 24, s. 12927-12937Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We report spectroelectrochemical studies to investigate the charge storage mechanism of composite polypyrrole/lignin electrodes. Renewable bioorganic electrode materials were produced by electropolymerization of pyrrole in the presence of a water-soluble lignin derivative acting as a dopant. The resulting composite exhibited enhanced charge storage abilities due to a lignin-based faradaic process, which was expressed after repeated electrochemical redox of the material. The in situ FTIR spectroelectrochemistry results show the formation of quinone groups, and reversible oxidation-reduction of these groups during charge-discharge experiments in the electrode materials. The most significant IR bands include carbonyl absorption near 1705 cm(-1), which is attributed to the creation of quinone moieties during oxidation, and absorption at 1045 cm(-1) which is due to hydroquinone moieties.

    sted, utgiver, år, opplag, sider
    ROYAL SOC CHEMISTRY, 2015
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-120069 (URN)10.1039/c5ta00788g (DOI)000356022800044 ()
    Merknad

    Funding Agencies|Knut and Alice Wallenberg foundation; Marie Curie network Renaissance; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

    Tilgjengelig fra: 2015-07-06 Laget: 2015-07-06 Sist oppdatert: 2017-12-04
    3. High performance PEDOT/lignin biopolymer composites for electrochemical supercapacitors
    Åpne denne publikasjonen i ny fane eller vindu >>High performance PEDOT/lignin biopolymer composites for electrochemical supercapacitors
    Vise andre…
    2016 (engelsk)Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, nr 5, s. 1838-1847Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Developing sustainable organic electrode materials for energy storage applications is an urgent task. We present a promising candidate based on the use of lignin, the second most abundant biopolymer in nature. This polymer is combined with a conducting polymer, where lignin as a polyanion can behave both as a dopant and surfactant. The synthesis of PEDOT/Lig biocomposites by both oxidative chemical and electrochemical polymerization of EDOT in the presence of lignin sulfonate is presented. The characterization of PEDOT/Lig was performed by UV-Vis-NIR spectroscopy, FTIR infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, cyclic voltammetry and galvanostatic charge-discharge. PEDOT doped with lignin doubles the specific capacitance (170.4 F g(-1)) compared to reference PEDOT electrodes (80.4 F g(-1)). The enhanced energy storage performance is a consequence of the additional pseudocapacitance generated by the quinone moieties in lignin, which give rise to faradaic reactions. Furthermore PEDOT/Lig is a highly stable biocomposite, retaining about 83% of its electroactivity after 1000 charge/discharge cycles. These results illustrate that the redox doping strategy is a facile and straightforward approach to improve the electroactive performance of PEDOT.

    sted, utgiver, år, opplag, sider
    ROYAL SOC CHEMISTRY, 2016
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-125323 (URN)10.1039/c5ta10096h (DOI)000368839200035 ()
    Merknad

    Funding Agencies|Power Papers project from the Knut and Alice Wallenberg foundation; Wallenberg Scholar grant from the Knut and Alice Wallenberg foundation; Marie Curie network Renaissance (NA); European Research Council by Starting Grant Innovative Polymers for Energy Storage (iPes) [306250]; Basque Government

    Tilgjengelig fra: 2016-02-23 Laget: 2016-02-19 Sist oppdatert: 2017-11-30
    Download (pdf)
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    presentationsbild
  • 12.
    Ali, Gulzar
    et al.
    University of Sindh, Pakistan.
    Tahira, Aneela
    Luleå University of Technology, Sweden.
    Begum Mallah, Arfana
    University of Sindh, Pakistan.
    Ahmed Mallah, Sarfraz
    University of Sindh, Pakistan.
    Ibupoto, Akila
    Shah Abdul Latif University, Pakistan.
    Ahmed Khand, Aftab
    Tsinghua University, Peoples R China.
    Baradi, Waryani
    University of Sindh, Pakistan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Yu, Cong
    Chinese Academic Science, Peoples R China.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan; Chinese Academic Science, Peoples R China.
    Functional CuO Microstructures for Glucose Sensing2018Inngår i: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 47, nr 2, s. 1519-1525Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    CuO microstructures are produced in the presence of water-soluble amino acids by hydrothermal method. The used amino acids include isoleucine, alpha alanine, and arginine as a soft template and are used for tuning the morphology of CuO nanostructures. The crystalline and morphological investigations were carried out by x-ray diffraction (XRD) and scanning electron microscopy techniques. The XRD study has shown that CuO material obtained in the presence of different amino acids is of high purity and all have the same crystal phase. The CuO microstructures prepared in the presence of arginine were used for the development of sensitive and selective glucose biosensor. The linear range for the glucose detection are from 0.001 mM to 30 mM and limit of detection was found to be 0.0005 mM. The sensitivity was estimated around 77 mV/decade. The developed biosensor is highly selective, sensitive, stable and reproducible. The glucose biosensor was used for the determination of real human blood samples and the obtained results are satisfactory. The CuO material is functional therefore can be capitalized in wide range of applications such as lithium ion batteries, all oxide solar cells and supercapacitors.

  • 13.
    Ali, Sharafat
    et al.
    Linnaeus University, Sweden; Corning Inc, NY 14831 USA.
    Paul, Biplab
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Magnusson, Roger
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Broitman, Esteban
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    Jonson, Bo
    Linnaeus University, Sweden.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Synthesis and characterization of the mechanical and optical properties of Ca-Si-O-N thin films deposited by RF magnetron sputtering2017Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 315, s. 88-94Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ca-Si-O-N thin films were deposited on commercial soda-lime silicate float glass, silica wafers and sapphire substrates by RF magnetron co-sputtering from Ca and Si targets in an Ar/N-2/O-2 gas mixture. Chemical composition, surface morphology, hardness, reduced elastic modulus and optical properties of the films were investigated using X-ray photoelectron spectroscopy, scanning electron microscopy, nanoindentation, and spectroscopic ellipsometry. It was found that the composition of the films can be controlled by the Ca target power, predominantly, and by the reactive gas flow. Thin films in the Ca-Si-O-N system are composed of N and Ca contents up to 31 eq. % and 60 eq. %, respectively. The films thickness ranges from 600 to 3000 nm and increases with increasing Ca target power. The films surface roughness varied between 2 and 12 nm, and approximately decreases with increasing power of Ca target. The hardness (4-12 GPa) and reduced elastic modulus (65-145 GPa) of the films increase and decrease with the N and Ca contents respectively. The refractive index (1.56-1.82) is primarily dictated by the N content. The properties are compared with findings for bulk glasses in the Ca-Si-(Al)-O-N systems, and it is concluded that Ca-Si-O-N thin films have higher values of hardness, elastic modulus and refractive index than bulk glasses of similar composition. (C) 2017 Elsevier B.V. All rights reserved.

    Fulltekst (pdf)
    fulltext
  • 14. Bestill onlineKjøp publikasjonen >>
    Alnoor, Hatim
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Toward the Optimization of Low-temperature Solution-based Synthesis of ZnO Nanostructures for Device Applications2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    One-dimensional (1D) nanostructures (NSs) of Zinc Oxide (ZnO) such as nanorods (NRs) have recently attracted considerable research attention due to their potential for the development of optoelectronic devices such as ultraviolet (UV) photodetectors and light-emitting diodes (LEDs). The potential of ZnO NRs in all these applications, however, would require synthesis of high crystal quality ZnO NRs with precise control over the optical and electronic properties. It is known that the optical and electronic properties of ZnO NRs are mostly influenced by the presence of native (intrinsic) and impurities (extrinsic) defects. Therefore, understanding the nature of these intrinsic and extrinsic defects and their spatial distribution is critical for optimizing the optical and electronic properties of ZnO NRs. However, identifying the origin of such defects is a complicated matter, especially for NSs, where the information on anisotropy is usually lost due to the lack of coherent orientation.

    Thus, the aim of this thesis is towards the optimization of the lowtemperature solution-based synthesis of ZnO NRs for device applications. In this connection, we first started with investigating the effect of the precursor solution stirring durations on the deep level defects concentration and their spatial distribution along the ZnO NRs. Then, by choosing the optimal stirring time, we studied the influence of ZnO seeding layer precursor’s types, and its molar ratios on the density of interface defects. The findings of these investigations were used to demonstrate ZnO NRs-based heterojunction LEDs. The ability to tune the point defects along the NRs enabled us further to incorporate cobalt (Co) ions into the ZnO NRs crystal lattice, where these ions could occupy the vacancies or interstitial defects through substitutional or interstitial doping. Following this, high crystal quality vertically welloriented ZnO NRs have been demonstrated by incorporating a small amount of Co into the ZnO crystal lattice. Finally, the influence of Co ions incorporation on the reduction of core-defects (CDs) in ZnO NRs was systematically examined using electron paramagnetic resonance (EPR).

    Delarbeid
    1. Effect of precursor solutions stirring on deep level defects concentration and spatial distribution in low temperature aqueous chemical synthesis of zinc oxide nanorods
    Åpne denne publikasjonen i ny fane eller vindu >>Effect of precursor solutions stirring on deep level defects concentration and spatial distribution in low temperature aqueous chemical synthesis of zinc oxide nanorods
    Vise andre…
    2015 (engelsk)Inngår i: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 5, nr 8, artikkel-id 087180Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Hexagonal c-axis oriented zinc oxide (ZnO) nanorods (NRs) with 120-300 nm diameters are synthesized via the low temperature aqueous chemical route at 80 degrees C on silver-coated glass substrates. The influence of varying the precursor solutions stirring durations on the concentration and spatial distributions of deep level defects in ZnO NRs is investigated. Room temperature micro-photoluminesnce (mu-PL) spectra were collected for all samples. Cathodoluminescence (CL) spectra of the as-synthesized NRs reveal a significant change in the intensity ratio of the near band edge emission (NBE) to the deep-level emission (DLE) peaks with increasing stirring durations. This is attributed to the variation in the concentration of the oxygen-deficiency with increasing stirring durations as suggested from the X-ray photoelectron spectroscopy analysis. Spatially resolved CL spectra taken along individual NRs revealed that stirring the precursor solutions for relatively short duration (1-3 h), which likely induced high super saturation under thermodynamic equilibrium during the synthesis process, is observed to favor the formation of point defects moving towards the tip of the NRs. In contrary, stirring for longer duration (5-15 h) will induce low super saturation favoring the formation of point defects located at the bottom of the NRs. These findings demonstrate that it is possible to control the concentration and spatial distribution of deep level defects in ZnO NRs by varying the stirring durations of the precursor solutions.

    sted, utgiver, år, opplag, sider
    AMER INST PHYSICS, 2015
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-122070 (URN)10.1063/1.4929981 (DOI)000360655900089 ()
    Merknad

    Funding Agencies|Avdanced Functional Materials (AFM) SFO project at Linkoping Univeristy, Sweden

    Tilgjengelig fra: 2015-12-18 Laget: 2015-10-19 Sist oppdatert: 2017-12-01
    2. Influence of ZnO seed layer precursor molar ratio on the density of interface defects in low temperature aqueous chemically synthesized ZnO nanorods/GaN light-emitting diodes
    Åpne denne publikasjonen i ny fane eller vindu >>Influence of ZnO seed layer precursor molar ratio on the density of interface defects in low temperature aqueous chemically synthesized ZnO nanorods/GaN light-emitting diodes
    Vise andre…
    2016 (engelsk)Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, nr 16, s. 165702-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Low temperature aqueous chemical synthesis (LT-ACS) of zinc oxide (ZnO) nanorods (NRs) has been attracting considerable research interest due to its great potential in the development of light-emitting diodes (LEDs). The influence of the molar ratio of the zinc acetate (ZnAc): KOH as a ZnO seed layer precursor on the density of interface defects and hence the presence of non-radiative recombination centers in LT-ACS of ZnO NRs/GaN LEDs has been systematically investigated. The material quality of the as-prepared seed layer as quantitatively deduced by the X-ray photoelectron spectroscopy is found to be influenced by the molar ratio. It is revealed by spatially resolved cathodoluminescence that the seed layer molar ratio plays a significant role in the formation and the density of defects at the n-ZnO NRs/p-GaN heterostructure interface. Consequently, LED devices processed using ZnO NRs synthesized with molar ratio of 1:5M exhibit stronger yellow emission (similar to 575 nm) compared to those based on 1:1 and 1:3M ratios as measured by the electroluminescence. Furthermore, seed layer molar ratio shows a quantitative dependence of the non-radiative defect densities as deduced from light-output current characteristics analysis. These results have implications on the development of high-efficiency ZnO-based LEDs and may also be helpful in understanding the effects of the ZnO seed layer on defect-related non-radiative recombination. Published by AIP Publishing.

    sted, utgiver, år, opplag, sider
    AMER INST PHYSICS, 2016
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-129174 (URN)10.1063/1.4947593 (DOI)000375929900043 ()
    Merknad

    Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]

    Tilgjengelig fra: 2016-06-13 Laget: 2016-06-13 Sist oppdatert: 2017-11-28
    3. Seed layer synthesis effect on the concentration of interface defects and emission spectra of ZnO nanorods/p-GaN light-emitting diode
    Åpne denne publikasjonen i ny fane eller vindu >>Seed layer synthesis effect on the concentration of interface defects and emission spectra of ZnO nanorods/p-GaN light-emitting diode
    2017 (engelsk)Inngår i: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 214, nr 1, artikkel-id 1600333Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    As the low-temperature aqueous chemical synthesis (LT-ACS), holds great promises for the synthesis of one-dimensional (1D) ZnO nanostructure-based light-emitting diodes (LEDs) and hence require parameter tuning for optimal performance. N-ZnO nanorods (NRs)/p-GaN heterojunction LEDs have been synthesized by the LT-ACS using ZnO nanoparticle (NPs) seed layers prepared with different precursor solutions. The effect of these seed layers on the interface defect properties and emission intensity of the as-synthesized n-Zn/p-GaN heterojunction LEDs has been demonstrated by spatially resolved cathodoluminescence (CL) and electroluminescence (EL) measurements, respectively. A significant reduction of the interface defects in the n-ZnO NRs/p-GaN heterostructure synthesized from a seed layer prepared from zinc acetate (ZnAc) with a mixture of potassium hydroxide (KOH) and hexamethylenetetramine (HMTA) (donated as ZKH seed) compared with those prepared from ZnAc and KOH (donated as ZK seed) is observed as revealed by spatially resolved CL. Consequently, the LEDs based on n-ZnO NRs/p-GaN prepared from ZKH seed show an improvement in the yellow emission (approximate to 578nm) compared to that based on the ZK seed as deduced from the electroluminescence measurements. The improvement in the yellow EL emission on the ZKH LED probably attributed to the low presence of the non-radiative defect as deduced by light-output current (L-I) characteristics analysis.

    sted, utgiver, år, opplag, sider
    WILEY-V C H VERLAG GMBH, 2017
    Emneord
    GaN; interface defects; light-emitting diodes; low-temperature aqueous chemical synthesis; seed layers; ZnO
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-136230 (URN)10.1002/pssa.201600333 (DOI)000394423400006 ()
    Merknad

    Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials (Faculty Grant SFO-Mat-LiU) at Linkoping University [2009-00971]

    Tilgjengelig fra: 2017-03-31 Laget: 2017-03-31 Sist oppdatert: 2017-11-29
    4. EPR investigation of pure and Co-doped ZnO oriented nanocrystals
    Åpne denne publikasjonen i ny fane eller vindu >>EPR investigation of pure and Co-doped ZnO oriented nanocrystals
    Vise andre…
    2017 (engelsk)Inngår i: NANOTECHNOLOGY, ISSN 0957-4484, Vol. 28, nr 3, artikkel-id 035705Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Pure and cobalt-doped zinc oxide aligned nanorods have been grown by the low-temperature (90 degrees C) aqueous chemical method on amorphous ZnO seed layer, deposited on a sapphire substrate. High crystallinity of these objects is demonstrated by the electron paramagnetic resonance investigation at liquid helium temperature. The successful incorporation of Co2+ ions in substitution of Zn2+ ones in the ZnO matrix has also been confirmed. A drastic reduction of intrinsic ZnO nanorods core defects is observed in the Co-doped samples, which enhances the structural quality of the NRs. The quantification of substitutional Co2+ ions in the ZnO matrix is achieved by comparison with a reference sample. The findings in this study indicate the potential of using the low-temperature aqueous chemical approach for synthesizing material for spintronics applications.

    sted, utgiver, år, opplag, sider
    IOP PUBLISHING LTD, 2017
    Emneord
    nanorods; magnetic properties; electron paramagnetic resonance; diluted magnetic semiconductors
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-134300 (URN)10.1088/1361-6528/28/3/035705 (DOI)000391289300001 ()27966469 (PubMedID)
    Merknad

    Funding Agencies|NATO project [SfP 984735]

    Tilgjengelig fra: 2017-02-06 Laget: 2017-02-03 Sist oppdatert: 2017-10-06
    5. An effective low-temperature solution synthesis of Co-doped [0001]-oriented ZnO nanorods
    Åpne denne publikasjonen i ny fane eller vindu >>An effective low-temperature solution synthesis of Co-doped [0001]-oriented ZnO nanorods
    Vise andre…
    2017 (engelsk)Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, nr 21, artikkel-id 215102Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We demonstrate an efficient possibility to synthesize vertically aligned pure zinc oxide (ZnO) and Co-doped ZnO nanorods (NRs) using the low-temperature aqueous chemical synthesis (90 degrees C). Two different mixing methods of the synthesis solutions were investigated for the Co-doped samples. The synthesized samples were compared to pure ZnO NRs regarding the Co incorporation and crystal quality. Electron paramagnetic resonance (EPR) measurements confirmed the substitution of Co2+ inside the ZnO NRs, giving a highly anisotropic magnetic Co2+ signal. The substitution of Zn2+ by Co2+ was observed to be combined with a drastic reduction in the core-defect (CD) signal (g similar to 1.956) which is seen in pure ZnO NRs. As revealed by the cathodoluminescence (CL), the incorporation of Co causes a slight red-shift of the UV peak position combined with an enhancement in the intensity of the defect-related yellow-orange emission compared to pure ZnO NRs. Furthermore, the EPR and the CL measurements allow a possible model of the defect configuration in the samples. It is proposed that the as-synthesized pure ZnO NRs likely contain Zn interstitial (Zn-i(+)) as CDs and oxygen vacancy (V-O) or oxygen interstitial (O-i) as surface defects. As a result, Co was found to likely occupy the Zn-i(+), leading to the observed CDs reduction and hence enhancing the crystal quality. These results open the possibility of synthesis of highly crystalline quality ZnO NRs-based diluted magnetic semiconductors using the low-temperature aqueous chemical method. Published by AIP Publishing.

    sted, utgiver, år, opplag, sider
    AMER INST PHYSICS, 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-138890 (URN)10.1063/1.4984314 (DOI)000402768900026 ()
    Merknad

    Funding Agencies|NATO [984735]

    Tilgjengelig fra: 2017-06-27 Laget: 2017-06-27 Sist oppdatert: 2017-10-06
    6. Core-defect reduction in ZnO nanorods by cobalt incorporation
    Åpne denne publikasjonen i ny fane eller vindu >>Core-defect reduction in ZnO nanorods by cobalt incorporation
    Vise andre…
    2017 (engelsk)Inngår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 28, nr 28, artikkel-id 285705Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Zinc oxide (ZnO) nanorods grown by the low-temperature (90 degrees C) aqueous chemical method with different cobalt concentration within the synthesis solution (from 0% to 15%), are studied by electron paramagnetic resonance (EPR), just above the liquid helium temperature. The anisotropic spectra of substitutional Co2+ reveal a high crystalline quality and orientation of the NRs, as well as the probable presence of a secondary disordered phase of ZnO: Co. The analysis of the EPR spectra indicates that the disappearance of the paramagnetic native core-defect (CD) at g similar to 1.96 is correlated with the apparition of the Co2+ ions lines, suggesting a gradual neutralization of the former by the latter. We show that only a little amount of cobalt in the synthesis solution (about 0.2%) is necessary to suppress almost all these paramagnetic CDs. This gives insight in the experimentally observed improvement of the crystal quality of diluted ZnO: Co nanorods, as well as into the control of paramagnetic defects in ZnO nanostructures.

    sted, utgiver, år, opplag, sider
    IOP PUBLISHING LTD, 2017
    Emneord
    nanorods; ZnO; physics defects; electron paramagnetic resonance
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-139388 (URN)10.1088/1361-6528/aa716a (DOI)000404344400005 ()28475103 (PubMedID)
    Merknad

    Funding Agencies|NATO project Science for Peace (SfP), Novel nanostructures [984735]

    Tilgjengelig fra: 2017-08-07 Laget: 2017-08-07 Sist oppdatert: 2017-10-06
    Fulltekst (pdf)
    Toward the Optimization of Low-temperature Solution-based Synthesis of ZnO Nanostructures for Device Applications
    Download (pdf)
    omslag
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    presentationsbild
  • 15.
    Alnoor, Hatim
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Pozina, Galia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Khranovskyy, Volodymyr
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Iandolo, Donata
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Influence of ZnO seed layer precursor molar ratio on the density of interface defects in low temperature aqueous chemically synthesized ZnO nanorods/GaN light-emitting diodes2016Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, nr 16, s. 165702-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Low temperature aqueous chemical synthesis (LT-ACS) of zinc oxide (ZnO) nanorods (NRs) has been attracting considerable research interest due to its great potential in the development of light-emitting diodes (LEDs). The influence of the molar ratio of the zinc acetate (ZnAc): KOH as a ZnO seed layer precursor on the density of interface defects and hence the presence of non-radiative recombination centers in LT-ACS of ZnO NRs/GaN LEDs has been systematically investigated. The material quality of the as-prepared seed layer as quantitatively deduced by the X-ray photoelectron spectroscopy is found to be influenced by the molar ratio. It is revealed by spatially resolved cathodoluminescence that the seed layer molar ratio plays a significant role in the formation and the density of defects at the n-ZnO NRs/p-GaN heterostructure interface. Consequently, LED devices processed using ZnO NRs synthesized with molar ratio of 1:5M exhibit stronger yellow emission (similar to 575 nm) compared to those based on 1:1 and 1:3M ratios as measured by the electroluminescence. Furthermore, seed layer molar ratio shows a quantitative dependence of the non-radiative defect densities as deduced from light-output current characteristics analysis. These results have implications on the development of high-efficiency ZnO-based LEDs and may also be helpful in understanding the effects of the ZnO seed layer on defect-related non-radiative recombination. Published by AIP Publishing.

  • 16.
    Amin, Sidra
    et al.
    Lulea Univ Technol, Sweden; Shaheed Benazir Bhutto Univ, Pakistan.
    Tahira, Aneela
    Lulea Univ Technol, Sweden.
    Solangi, Amber
    Univ Sindh, Pakistan.
    Beni, Valerio
    Res Inst Sweden, Sweden.
    Morante, J. R.
    Catalonia Inst Energy Res IREC, Spain.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Mazzaro, Raffaello
    Lulea Univ Technol, Sweden.
    Ibupoto, Zafar Hussain
    Lulea Univ Technol, Sweden; Univ Sindh, Pakistan.
    Vomiero, Alberto
    Lulea Univ Technol, Sweden.
    A practical non-enzymatic urea sensor based on NiCo2O4 nanoneedles2019Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, nr 25, s. 14443-14451Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose a new facile electrochemical sensing platform for determination of urea, based on a glassy carbon electrode (GCE) modified with nickel cobalt oxide (NiCo2O4) nanoneedles. These nanoneedles are used for the first time for highly sensitive determination of urea with the lowest detection limit (1 mu M) ever reported for the non-enzymatic approach. The nanoneedles were grown through a simple and low-temperature aqueous chemical method. We characterized the structural and morphological properties of the NiCo2O4 nanoneedles by TEM, SEM, XPS and XRD. The bimetallic nickel cobalt oxide exhibits nanoneedle morphology, which results from the self-assembly of nanoparticles. The NiCo2O4 nanoneedles are exclusively composed of Ni, Co, and O and exhibit a cubic crystalline phase. Cyclic voltammetry was used to study the enhanced electrochemical properties of a NiCo2O4 nanoneedle-modified GCE by overcoming the typical poor conductivity of bare NiO and Co3O4. The GCE-modified electrode is highly sensitive towards urea, with a linear response (R-2 = 0.99) over the concentration range 0.01-5 mM and with a detection limit of 1.0 mu M. The proposed non-enzymatic urea sensor is highly selective even in the presence of common interferents such as glucose, uric acid, and ascorbic acid. This new urea sensor has good viability for urea analysis in urine samples and can represent a significant advancement in the field, owing to the simple and cost-effective fabrication of electrodes, which can be used as a promising analytical tool for urea estimation.

    Fulltekst (pdf)
    fulltext
  • 17.
    Andersson Ersman, Peter
    et al.
    RISE Acreo, Sweden.
    Lassnig, Roman
    RISE Acreo, Sweden.
    Strandberg, Jan
    RISE Acreo, Sweden.
    Tu, Deyu
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Keshmiri, Vahid
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Forchheimer, Robert
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Fabiano, Simone
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Gustafsson, Goran
    RISE Acreo, Sweden.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    All-printed large-scale integrated circuits based on organic electrochemical transistors2019Inngår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikkel-id 5053Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The communication outposts of the emerging Internet of Things are embodied by ordinary items, which desirably include all-printed flexible sensors, actuators, displays and akin organic electronic interface devices in combination with silicon-based digital signal processing and communication technologies. However, hybrid integration of smart electronic labels is partly hampered due to a lack of technology that (de)multiplex signals between silicon chips and printed electronic devices. Here, we report all-printed 4-to-7 decoders and seven-bit shift registers, including over 100 organic electrochemical transistors each, thus minimizing the number of terminals required to drive monolithically integrated all-printed electrochromic displays. These relatively advanced circuits are enabled by a reduction of the transistor footprint, an effort which includes several further developments of materials and screen printing processes. Our findings demonstrate that digital circuits based on organic electrochemical transistors (OECTs) provide a unique bridge between all-printed organic electronics (OEs) and low-cost silicon chip technology for Internet of Things applications.

    Fulltekst (pdf)
    fulltext
  • 18.
    Anwar, Nargis
    et al.
    Dundalk Inst Technol, Ireland.
    Armstrong, Gordon
    Univ Limerick, Ireland.
    Laffir, Fathima
    Univ Limerick, Ireland.
    Dickinson, Calum
    Univ Limerick, Ireland.
    Vagin, Mikhail
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    McCormac, Timothy
    Dundalk Inst Technol, Ireland.
    Redox switching of polyoxometalate-doped polypyrrole films in ionic liquid media2018Inngår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 265, s. 254-258Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The surface immobilization of the parent Dawson polyoxometalate (POM) as a counter-ion for the electropolymerization of polypyrrole (PPy) or as an electrode-adhered solid was utilized for voltammetric studies of the surface adhered POM in room temperature ionic liquids (RTIL). Illustrating the efficiency of intermediate stabilization, voltammetry at POM-modified electrodes in a PF6-based RTIL revealed richer redox behaviour and higher stabilization in comparison with aqueous electrolytes and with BF4-based RTIL, respectively. High stability of the POM-doped PPy towards continuous charge-discharge voltammetric redox cycles was confirmed by minor changes in film morphology observed after the cycling in RTILs. (c) 2017 Elsevier Ltd. All rights reserved.

    Fulltekst (pdf)
    fulltext
  • 19.
    Ao, Xiang
    et al.
    Huazhong University of Science and Technology, Peoples R China.
    Jiang, Jianjun
    Huazhong University of Science and Technology, Peoples R China.
    Ruan, Yunjun
    Huazhong University of Science and Technology, Peoples R China.
    Li, Zhishan
    Huazhong University of Science and Technology, Peoples R China.
    Zhang, Yi
    Wuhan Institute Technology, Peoples R China.
    Sun, Jianwu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Wang, Chundong
    Huazhong University of Science and Technology, Peoples R China; Chinese Academic Science, Peoples R China.
    Honeycomb-inspired design of ultrafine SnO2@C nanospheres embedded in carbon film as anode materials for high performance lithium- and sodium-ion battery2017Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 359, s. 340-348Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tin oxide (SnO2) has been considered as one of the most promising anodes for advanced rechargeable batteries due to its advantages such as high energy density, earth abundance and environmental friendly. However, its large volume change during the Li-Sn/Na-Sn alloying and de-alloying processes will result in a fast capacity degradation over a long term cycling. To solve this issue, in this work we design and synthesize a novel honeycomb-like composite composing of carbon encapsulated SnO2 nanospheres embedded in carbon film by using dual templates of SiO2 and NaCl. Using these composites as anodes both in lithium ion batteries and sodium-ion batteries, no discernable capacity degradation is observed over hundreds of long term cycles at both low current density (100 mA g(-1)) and high current density (500 mA g(-1)). Such a good cyclic stability and high delivered capacity have been attributed to the high conductivity of the supported carbon film and hollow encapsulated carbon shells, which not only provide enough space to accommodate the volume expansion but also prevent further aggregation of SnO2 nanoparticles upon cycling. By engineering electrodes of accommodating high volume expansion, we demonstrate a prototype to achieve high performance batteries, especially high-power batteries. (C) 2017 Elsevier B.V. All rights reserved.

    Fulltekst (pdf)
    fulltext
  • 20.
    Arain, Munazza
    et al.
    University of Sindh, Pakistan.
    Nafady, Ayman
    King Saud University, Saudi Arabia; Sohag University, Egypt.
    Sirajuddin,
    Univ Sindh, Pakistan.
    Ibupoto, ZH
    Univ Sindh, Pakistan.
    Sherazi, Syed Tufail Hussain
    University of Sindh, Pakistan.
    Shaikh, Tayyaba
    University of Sindh, Pakistan.
    Khan, Hamayun
    Islamia Coll University, Pakistan.
    Alsalme, Ali
    King Saud University, Saudi Arabia.
    Niaz, Abdul
    Bannu University of Science and Technology, Pakistan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Simpler and highly sensitive enzyme-free sensing of urea via NiO nanostructures modified electrode2016Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, nr 45, s. 39001-39006Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, NiO nanostructures were synthesized via a hydrothermal process using ascorbic acid as doping agent in the presence of ammonia. As prepared nanostructures were characterized using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) specific surface area analysis, and thermogravimetric analysis (TGA). These analyses showed that these nanostructures are in the form of cotton-like porous material and crystalline in nature. Furthermore, the average size of these NiO crystallites was estimated to be 3.8 nm. These nanostructures were investigated for their potential to be a highly sensitive and selective enzyme-free sensor for detection of urea after immobilizing on a glassy carbon electrode (GCE) using 0.1% Nafion as binder. The response of this as developed amperometric sensor was linear in the range of 100-1100 mu M urea with a R-2 value of 0.990 and limit of detection (LOD) of 10 mu M. The sensor responded negligibly to various interfering species including glucose, uric acid, and ascorbic acid. This sensor was applied successfully for determining urea in real water samples such as mineral water, tap water, and river water with acceptable recovery.

    Fulltekst (pdf)
    fulltext
  • 21.
    Armakavicius, Nerijus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Free charge carrier properties in group III nitrides and graphene studied by THz-to-MIR ellipsometry and optical Hall effect2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Development of silicon based electronics have revolutionized our every day life during the last five decades. Nowadays silicon based devices operate close to their theoretical limits that is becoming a bottleneck for further progress. In particular, for the growing field of high frequency and high power electronics, silicon cannot offer the required properties. Development of materials capable of providing high current densities, carrier mobilities and high breakdown fields is crucial for further progress in state of the art electronics.

    Epitaxial graphene grown on semi-insulating silicon carbide substrates has a high potential to be integrated in current planar device technologies. High electron mobilities and sheet carrier densities make graphene extremely attractive for high frequency analog applications. One of the remaining challenges is the interaction of epitaxial graphene with the substrate. Typically, much lower free charge carrier mobilities, compared to free standing graphene, and doping, due to charge transfer from the substrate, is reported. Thus, a good understanding of the intrinsic free charge carriers properties and the factors affecting them is very important for further development of epitaxial graphene.

    Group III-nitrides have been extensively studied and already have proven their high efficiency as light emitting diodes for short wavelengths. High carrier mobilities and breakdown electric fields were demonstrated for group III-nitrides, making them attractive for high frequency and high power applications. Currently, In-rich InGaN alloys and AlGaN/GaN high electron mobility structures are of high interest for the research community due to open fundamental questions such as free charge carrier properties at high temperatures and wavefunction hybridization in AlGaN/GaN heterostructures.

    Electrical characterization techniques, commonly used for the determination of free charge carrier properties, require good ohmic and Schottky contacts, which in certain cases can be difficult to achieve. Access to electrical properties of buried conductive channels in multilayered structures requires modification of samples and good knowledge of the electrical properties of all electrical junctions within the structure. Moreover, the use of contacts to electrically characterize two-dimensional electronic materials, such as graphene, can alter their intrinsic properties. Furthermore, the determination of effective mass parameters commonly employs cyclotron resonance and Shubnikov-de Haas oscillations measurements, which require long scattering times of free charge carriers, high magnetic fields and low temperatures.

    The optical Hall effect is an external magnetic-field induced birefringence of conductive layers due to the free charge carriers interaction with long-wavelength electromagnetic waves under the influence of the Lorentz force. The optical Hall effect can be measured by generalized ellipsometry and provides a powerful method for the determination of free charge carrier properties in a non-destructive and contactless manner. The optical Hall effect measurements can provide quantitative information about free charge carrier type, concentration, mobility and effective mass parameters at temperatures ranging from few kelvins to room temperature and above. It further allows to differentiate the free charge carrier properties of individual layers in multilayer samples. The employment of a backside cavity for transparent samples can enhance the optical Hall effect and allows to access free charge carrier properties at relatively low magnetic fields using permanent magnet.

    The optical Hall effect measurements at mid-infrared spectral range can be used to probe quantum mechanical phenomena such as Landau levels in graphene. The magnetic field dependence of the inter-Landau level transition energies and optical polarization selection rules provide information about coupling properties between graphene layers and the electronic band structure.

    Measurement of the optical Hall effect by generalized ellipsometry is an indirect technique requiring subsequent data analysis. Parameterized optical models are fitted to match experimentally measured ellipsometric spectra by varying physically significant model parameters. Analysis of the generalized ellipsometry data at long wavelengths for samples containing free charge carriers by optical models based on the classical Drude formulation, augmented with an external magnetic field contribution, allows to extract carrier concentration, mobility and effective mass parameters.

    The development of the integrated FIR and THz frequency-domain ellipsometer at the Terahertz Materials Analysis Center in Linköping University was part of the graduate studies presented in this dissertation. The THz ellipsometer capabilities are demonstrated by determination of Si and sapphire optical constants, and free charge carrier properties of two-dimensional electron gas in GaN-based high electron mobility transistor structures. The THz ellipsometry is further shown to be capable of determining free charge carrier properties and following their changes upon variation of ambient conditions in atomically thin layers with an example of epitaxial graphene.

    A potential of the THz OHE with the cavity enhancement (THz-CE-OHE) for determination of the free charge carrier properties in atomically thin layers were demonstrated by the measurements of the carrier properties in monolayer and multilayer epitaxial graphene on Si-face 4H-SiC. The data analysis revealed p-type doping for monolayer graphene with a carrier density in the low 1012 cm-2 range and a carrier mobility of 1550 cm2V-1s-1. For the multilayer graphene, n-type doping with a carrier density in the low 1013 cm-2 range, a mobility of 470 cm2V-1s-1 and an effective mass of (0.14 ± 0.03)m0 were extracted. Different type of doping among monolayer and multilayer graphene is explained as a result of different hydrophobicity among samples.

    Further, we have employed THz-CE-OHE to determine for the first time anisotropic mobility parameter in quasi-free-standing bilayer epitaxial graphene induced by step-like surface morphology of 4H-SiC. Correlation of atomic force microscopy, Raman scattering spectroscopy, scanning probe Kelvin probe microscopy, low energy electron microscopy and diffraction analysis allows us to investigate the possible scattering mechanisms and suggests that anisotropic mobility is induced by varying local mobility parameter due to interaction between graphene and underlaying substrate.

    The origin of the layers decoupling in multilayer graphene on C-face 4H-SiC was studied by MIR-OHE, transmission electron microscopy and electron energy loss spectroscopy. The results revealed the decoupling of the layers induced by the increased interlayer spacing which is attributed to the Si atoms trapped between graphene layers.

    MIR ellipsometry and MIR-OHE measurements were employed to determine the electron effective mass in a wurtzite In0.33Ga0.67N epitaxial layer. The data analysis revealed the effective mass parameters parallel and perpendicular to the c-axis which can be considered as equal within sensitivity of our measurements. The determined effective mass is consistent with linear dependence on the In content.

    Analysis of the free charge carrier properties in AlGaN/GaN high electron mobility structures with modified interfaces showed that AlGaN/GaN interface structure has a significant effect on the mobility parameter. A sample with a sharp interface layers exhibits a record mobility of 2332 ± 73 cm2V-1s-1. The determined effective mass parameters showed an increase compared to the bulk GaN value, which is attributed to the penetration of the electron wavefunction into the AlGaN barrier layer.

    Temperature dependence of free charge carrier properties in GaN-based high electron mobility transistor structures with AlGaN and InAlN barrier layers were measured by terahertz optical Hall effect technique in a temperature range from 7.2 K to 398 K. The results revealed strong changes in the effective mass and mobility parameters. At temperatures below 57 K very high carrier mobility parameters above 20000 cm2V-1s-1 for AlGaN-barrier sample and much lower mobilities of ~ 5000 cm2V-1s-1 for InAlN-barrier sample were obtained. At low temperatures the effective mass parameters for both samples are very similar to bulk GaN value, while at temperatures above 131 K effective mass shows a strong increase with temperature. The effective masses of 0.344 m0 (@370 K) and 0.439 m0 (@398 K) were obtained for AlGaN- and InAlN-barrier samples, respectively. We discussed the possible origins of effective mass enhancement in high electron mobility transistor structures.  

    Delarbeid
    1. Advanced Terahertz Frequency-Domain Ellipsometry Instrumentation for In Situ and Ex Situ Applications
    Åpne denne publikasjonen i ny fane eller vindu >>Advanced Terahertz Frequency-Domain Ellipsometry Instrumentation for In Situ and Ex Situ Applications
    Vise andre…
    2018 (engelsk)Inngår i: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, Vol. 8, nr 3, s. 257-270Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We present a terahertz (THz) frequency-domain spectroscopic ellipsometer design that suppresses formation of standing waves by use of stealth technology approaches. The strategy to suppress standing waves consists of three elements geometry, coating, and modulation. The instrument is based on the rotating analyzer ellipsometer principle and can incorporate various sample compartments, such as a superconducting magnet, in situ gas cells, or resonant sample cavities, for example. A backward wave oscillator and three detectors are employed, which permit operation in the spectral range of 0.1–1 THz (3.3–33 cm−1 or 0.4–4 meV). The THz frequency-domain ellipsometer allows for standard and generalized ellipsometry at variable angles of incidence in both reflection and transmission configurations. The methods used to suppress standing waves and strategies for an accurate frequency calibration are presented. Experimental results from dielectric constant determination in anisotropic materials, and free charge carrier determination in optical Hall effect (OHE), resonant-cavity enhanced OHE, and in situ OHE experiments are discussed. Examples include silicon and sapphire optical constants, free charge carrier properties of two-dimensional electron gas in a group III nitride high electron mobility transistor structure, and ambient effects on free electron mobility and density in epitaxial graphene.

    sted, utgiver, år, opplag, sider
    Institute of Electrical and Electronics Engineers (IEEE), 2018
    Emneord
    Ellipsometry, Frequency-domain analysis, Instruments, Measurement by laser beam, Coherence, Dielectrics, Laser beams
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-147883 (URN)10.1109/TTHZ.2018.2814347 (DOI)000431446900001 ()2-s2.0-85045191738 (Scopus ID)
    Merknad

    Funding agencies: Swedish Foundation for Strategic Research (SSF) [FFL12-0181, RIF14-055]; AForsk [13-318]; Swedish Research Council (VR) [2013-5580, 2016-00889]; Swedish Governmental Agency for Innovation Systems (VINNOVA Grant) [2011-03486]; Swedish Government Strategic 

    Tilgjengelig fra: 2018-05-18 Laget: 2018-05-18 Sist oppdatert: 2019-03-05bibliografisk kontrollert
    2. Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies
    Åpne denne publikasjonen i ny fane eller vindu >>Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies
    Vise andre…
    2017 (engelsk)Inngår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 421, s. 357-360Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Cavity-enhanced optical Hall effect at terahertz (THz) frequencies is employed to determine the free charge carrier properties in epitaxial graphene (EG) with different number of layers grown by high-temperature sublimation on 4H-SiC(0001). We find that one monolayer (ML) EG possesses p-type conductivity with a free hole concentration in the low 1012 cmᅵᅵᅵ2 range and a free hole mobility parameter as high as 1550 cm2/Vs. We also find that 6 ML EG shows n-type doping behavior with a much lower free electron mobility parameter of 470 cm2/Vs and an order of magnitude higher free electron density in the low 1013 cmᅵᅵᅵ2 range. The observed differences are discussed. The cavity-enhanced THz optical Hall effect is demonstrated to be an excellent tool for contactless access to the type of free charge carriers and their properties in two-dimensional materials such as EG.

    sted, utgiver, år, opplag, sider
    Elsevier, 2017
    Emneord
    THz optical Hall effect, Epitaxial graphene, Free charge carrier properties
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-132407 (URN)10.1016/j.apsusc.2016.10.023 (DOI)000408756700015 ()
    Merknad

    Funding agencies: Swedish Research Council (VR) [2013-5580]; Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program [2011-03486, 2014-04712]; Swedish foundation for strategic research (SSF) [FFL12-0181, RIF14-055]

    Tilgjengelig fra: 2016-11-09 Laget: 2016-11-09 Sist oppdatert: 2019-03-05bibliografisk kontrollert
    3. Electron effective mass in In0.33Ga0.67N determined by mid-infrared optical Hall effect
    Åpne denne publikasjonen i ny fane eller vindu >>Electron effective mass in In0.33Ga0.67N determined by mid-infrared optical Hall effect
    Vise andre…
    2018 (engelsk)Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 112, nr 8, artikkel-id 082103Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Mid-infrared optical Hall effect measurements are used to determine the free charge carrier parameters of an unintentionally doped wurtzite-structure c-plane oriented In0.33Ga0.67N epitaxial layer. Room temperature electron effective mass parameters of m(perpendicular to)* = (0.205 +/- 0.013) m(0) and m(parallel to)* = (0.204 +/- 0.016) m(0) for polarization perpendicular and parallel to the c-axis, respectively, were determined. The free electron concentration was obtained as (1.7 +/- 0.2) x 10(19) cm(-3). Within our uncertainty limits, we detect no anisotropy for the electron effective mass parameter and we estimate the upper limit of the possible effective mass anisotropy as 7%. We discuss the influence of conduction band nonparabolicity on the electron effective mass parameter as a function of In content. The effective mass parameter is consistent with a linear interpolation scheme between the conduction band mass parameters in GaN and InN when the strong nonparabolicity in InN is included. The In0.33Ga0.67N electron mobility parameter was found to be anisotropic, supporting previous experimental findings for wurtzite-structure GaN, InN, and AlxGa1-xN epitaxial layers with c-plane growth orientation. Published by AIP Publishing.

    sted, utgiver, år, opplag, sider
    AMER INST PHYSICS, 2018
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-145763 (URN)10.1063/1.5018247 (DOI)000425977500010 ()
    Merknad

    Funding Agencies|Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program [2011-03486]; Swedish Research Council (VR) [2016-00889]; Competence Center Program [2016-05190]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University, Faculty Grant SFO Mat LiU [2009-00971]; University of Nebraska-Lincoln; Swedish Foundation for Strategic Research (SSF) [FL12-0181, RIF14-055, EM16-0024]; J. A. Woollam Foundation; J. A. Woollam Co., Inc.; National Science Foundation [MRSEC DMR 1420645, CMMI 1337856, EAR 1521428]

    Tilgjengelig fra: 2018-03-22 Laget: 2018-03-22 Sist oppdatert: 2019-03-05
    4. Properties of two-dimensional electron gas in AlGaN/GaN HEMT structures determined by cavity-enhanced THz optical Hall effect
    Åpne denne publikasjonen i ny fane eller vindu >>Properties of two-dimensional electron gas in AlGaN/GaN HEMT structures determined by cavity-enhanced THz optical Hall effect
    Vise andre…
    2016 (engelsk)Inngår i: Physica Status Solidi C-Current Topics in Solid State Physics, Vol 13 No 5-6, Wiley-VCH Verlagsgesellschaft, 2016, Vol. 13, nr 5-6, s. 369-373Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In this work we employ terahertz (THz) ellipsometry to determine two-dimensional electron gas (2DEG) density, mobility and effective mass in AlGaN/GaN high electron mobility transistor structures grown on 4H-SiC substrates. The effect of the GaN interface exposure to low-flow-rate trimethylaluminum (TMA) on the 2DEG properties is studied. The 2DEG effective mass and sheet density are determined tobe in the range of 0.30-0.32m0 and 4.3-5.5×1012 cm–2, respectively. The 2DEG effective mass parameters are found to be higher than the bulk effective mass of GaN, which is discussed in view of 2DEG confinement. It is shown that exposure to TMA flow improves the 2DEG mobility from 2000 cm2/Vs to values above 2200 cm2/Vs. A record mobility of 2332±61 cm2/Vs is determined for the sample with GaN interface exposed to TMA for 30 s. This improvement in mobility is suggested to be due to AlGaN/GaN interface sharpening causing the reduction of interface roughness scattering of electrons in the 2DEG.

    sted, utgiver, år, opplag, sider
    Wiley-VCH Verlagsgesellschaft, 2016
    Serie
    Physica Status Solidi C-Current Topics in Solid State Physics, ISSN 1862-6351
    Emneord
    AlGaN/GaN HEMTs, THz ellipsometry, 2DEG properties, THz optical Hall effect
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-133135 (URN)10.1002/pssc.201510214 (DOI)000387957200045 ()
    Konferanse
    11th International Conference on Nitride Semiconductors (ICNS), Beijing, China, August 30-September 4. 2015
    Tilgjengelig fra: 2016-12-12 Laget: 2016-12-09 Sist oppdatert: 2019-03-05bibliografisk kontrollert
    Fulltekst (pdf)
    Free charge carrier properties in group III nitrides and graphene studied by THz-to-MIR ellipsometry and optical Hall effect
    Download (png)
    presentationsbild
  • 22. Bestill onlineKjøp publikasjonen >>
    Armakavicius, Nerijus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Study of novel electronic materials by mid-infrared and terahertz optical Hall effect2017Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Development of silicon based electronics have revolutionized our every day life during the last three decades. Nowadays Si based devices operate close to their theoretical limits that is becoming a bottleneck for further progress. In particular, for the growing field of high frequency and high power electronics, Si cannot offer the required properties. Development of materials capable of providing high current densities, carrier mobilities and high breakdown fields is crucial for a progress in state of the art electronics.

    Epitaxial graphene grown on semi-insulating silicon carbide substrates has a high potential to be integrated in the current planar device technologies. High electron mobilities and sheet carrier densities make graphene extremely attractive for high frequency analog applications. One of the remaining challenges is the interaction of epitaxial graphene with the substrate. Typically, much lower free charge carrier mobilities, compared to free standing graphene, and doping, due to charge transfer from the substrate, is reported. Thus, a good understanding of the intrinsic free charge carriers properties and the factors affecting them is very important for further development of epitaxial graphene.

    III-group nitrides have been extensively studied and already have proven their high efficiency as light sources for short wavelengths. High carrier mobilities and breakdown electric fields were demonstrated for III-group nitrides, making them attractive for high frequency and high power applications. Currently, In-rich InGaN alloys and AlGaN/GaN high electron mobility structures are of high interest for the research community due to open fundamental questions.

    Electrical characterization techniques, commonly used for the determination of free charge carrier properties, require good ohmic and Schottky contacts, which in certain cases can be difficult to achieve. Access to electrical properties of buried conductive channels in multilayered structures requires modification of samples and good knowledge of the electrical properties of all electrical contact within the structure. Moreover, the use of electrical contacts to electrically characterize two-dimensional electronic materials, such as graphene, can alter their intrinsic properties. Furthermore, the determination of effective mass parameters commonly employs cyclotron resonance and Shubnikov-de Haas oscillations measurements, which require long scattering times of free charge carriers, high magnetic fields and low temperatures.

    The optical Hall effect is an external magnetic field induced optical anisotropy in  conductive layers due to the motion of the free charge carriers under the influence of the Lorentz force, and is equivalent to the electrical Hall effect at optical frequencies. The optical Hall effect can be measured by generalized ellipsometry and provides a powerful method for the determination of free charge carrier properties in a non-destructive and contactless manner. In principle, a single optical Hall effect measurement can provide quantitative information about free charge carrier types, concentrations, mobilities and effective mass parameters at temperatures ranging from few kelvins to room temperature and above. Further, it was demonstrated that for transparent samples, a backside cavity can be employed to enhance the optical Hall effect.

    Measurement of the optical Hall effect by generalized ellipsometry is an indirect technique requiring subsequent data analysis. Parameterized optical models are fitted to match experimentally measured ellipsometric data by varying physically significant parameters. Analysis of the optical response of samples, containing free charge carriers, employing optical models based on the classical Drude model, which is augmented with an external magnetic field contribution, provide access to the free charge carrier properties.

    The main research results of the graduate studies presented in this licentiate thesis are summarized in the five scientific papers.

    Paper I. Description of the custom-built terahertz frequency-domain spectroscopic ellipsometer at Linköping University. The terahertz ellipsometer capabilities are demonstrated by an accurate determination of the isotropic and anisotropic refractive indices of silicon and m-plane sapphire, respectively. Further, terahertz optical Hall effect measurements of an AlGaN/GaN high electron mobility structures were employed to extract the two-dimensional electron gas sheet density, mobility and effective mass parameters. Last, in-situ optical Hall effect measurement on epitaxial graphene in a gas cell with controllable environment, were used to study the effects of environmental doping on the mobility and carrier concentration.

    Paper II. Presents terahertz cavity-enhanced optical Hall measurements of the monolayer and multilayer epitaxial graphene on semi-insulating 4H-SiC (0001) substrates. The data analysis revealed p-type doping for monolayer graphene with a carrier density in the low 1012 cm−2 range and a carrier mobility of 1550 cm2/V·s. For the multilayer epitaxial graphene, n-type doping with a carrier density in the low 1013 cm−2 range, a mobility of 470 cm2/V·s and an effective mass of (0.14 ± 0.03) m0 were extracted. The measurements demonstrate that cavity-enhanced optical Hall effect measurements can be applied to study electronic properties of two-dimensional materials.

    Paper III. Terahertz cavity-enhanced optical Hall effect measurements are employed to study anisotropic transport in as-grown monolayer, quasi free-standing monolayer and quasi free-standing bilayer epitaxial graphene on semi-insulating 4H-SiC (0001) substrates. The data analysis revealed a strong anisotropy in the carrier mobilities of the quasi freestanding bilayer graphene. The anisotropy is demonstrated to be induced by carriers scattering at the step edges of the SiC, by showing that the mobility is higher along the step than across them. The scattering mechanism is discussed based on the results of the optical Hall effect, low-energy electron microscopy, low-energy electron diffraction and Raman measurements.

    Paper IV. Mid-infrared spectroscopic ellipsometry and mid-infrared optical Hall effect measurements are employed to determine the electron effective mass in an In0.33Ga0.67N epitaxial layer. The data analysis reveals slightly anisotropic effective mass and carrier mobility parameters together with the optical phonon frequencies and broadenings.

    Paper V. Terahertz cavity-enhanced optical Hall measurements are employed to study the free charge carrier properties in a set of AlGaN/GaN high electron mobility structures with modified interfaces. The results show that the interface structure has a significant effect on the free charge carrier mobility and that the sample with a sharp interface between an AlGaN barrier and a GaN buffer layers exhibits a record mobility of 2332±73 cm2/V·s. The determined effective mass parameters showed an increase compared to the GaN value, that is attributed the the penetration of the electron wavefunction into the AlGaN barrier layer.

    Delarbeid
    1. Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies
    Åpne denne publikasjonen i ny fane eller vindu >>Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies
    Vise andre…
    2017 (engelsk)Inngår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 421, s. 357-360Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Cavity-enhanced optical Hall effect at terahertz (THz) frequencies is employed to determine the free charge carrier properties in epitaxial graphene (EG) with different number of layers grown by high-temperature sublimation on 4H-SiC(0001). We find that one monolayer (ML) EG possesses p-type conductivity with a free hole concentration in the low 1012 cmᅵᅵᅵ2 range and a free hole mobility parameter as high as 1550 cm2/Vs. We also find that 6 ML EG shows n-type doping behavior with a much lower free electron mobility parameter of 470 cm2/Vs and an order of magnitude higher free electron density in the low 1013 cmᅵᅵᅵ2 range. The observed differences are discussed. The cavity-enhanced THz optical Hall effect is demonstrated to be an excellent tool for contactless access to the type of free charge carriers and their properties in two-dimensional materials such as EG.

    sted, utgiver, år, opplag, sider
    Elsevier, 2017
    Emneord
    THz optical Hall effect, Epitaxial graphene, Free charge carrier properties
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-132407 (URN)10.1016/j.apsusc.2016.10.023 (DOI)000408756700015 ()
    Merknad

    Funding agencies: Swedish Research Council (VR) [2013-5580]; Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program [2011-03486, 2014-04712]; Swedish foundation for strategic research (SSF) [FFL12-0181, RIF14-055]

    Tilgjengelig fra: 2016-11-09 Laget: 2016-11-09 Sist oppdatert: 2019-03-05bibliografisk kontrollert
    2. Properties of two-dimensional electron gas in AlGaN/GaN HEMT structures determined by cavity-enhanced THz optical Hall effect
    Åpne denne publikasjonen i ny fane eller vindu >>Properties of two-dimensional electron gas in AlGaN/GaN HEMT structures determined by cavity-enhanced THz optical Hall effect
    Vise andre…
    2016 (engelsk)Inngår i: Physica Status Solidi C-Current Topics in Solid State Physics, Vol 13 No 5-6, Wiley-VCH Verlagsgesellschaft, 2016, Vol. 13, nr 5-6, s. 369-373Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In this work we employ terahertz (THz) ellipsometry to determine two-dimensional electron gas (2DEG) density, mobility and effective mass in AlGaN/GaN high electron mobility transistor structures grown on 4H-SiC substrates. The effect of the GaN interface exposure to low-flow-rate trimethylaluminum (TMA) on the 2DEG properties is studied. The 2DEG effective mass and sheet density are determined tobe in the range of 0.30-0.32m0 and 4.3-5.5×1012 cm–2, respectively. The 2DEG effective mass parameters are found to be higher than the bulk effective mass of GaN, which is discussed in view of 2DEG confinement. It is shown that exposure to TMA flow improves the 2DEG mobility from 2000 cm2/Vs to values above 2200 cm2/Vs. A record mobility of 2332±61 cm2/Vs is determined for the sample with GaN interface exposed to TMA for 30 s. This improvement in mobility is suggested to be due to AlGaN/GaN interface sharpening causing the reduction of interface roughness scattering of electrons in the 2DEG.

    sted, utgiver, år, opplag, sider
    Wiley-VCH Verlagsgesellschaft, 2016
    Serie
    Physica Status Solidi C-Current Topics in Solid State Physics, ISSN 1862-6351
    Emneord
    AlGaN/GaN HEMTs, THz ellipsometry, 2DEG properties, THz optical Hall effect
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-133135 (URN)10.1002/pssc.201510214 (DOI)000387957200045 ()
    Konferanse
    11th International Conference on Nitride Semiconductors (ICNS), Beijing, China, August 30-September 4. 2015
    Tilgjengelig fra: 2016-12-12 Laget: 2016-12-09 Sist oppdatert: 2019-03-05bibliografisk kontrollert
    Fulltekst (pdf)
    Study of novel electronic materials by mid-infrared and terahertz optical Hall effect
    Download (pdf)
    omslag
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    presentationsbild
  • 23.
    Ashaduzzaman, Md
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten. University of Dhaka, Bangladesh.
    Anto Antony, Aswathi
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Murugan, N. Arul
    Royal Institute Technology, Sweden.
    Deshpande, Swapneel R.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Turner, Anthony
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Tiwari, Ashutosh
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten. Tekidag AB, UCS, S-58330 Linkoping, Sweden.
    Studies on an on/off-switchable immunosensor for troponin T2015Inngår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 73, s. 100-107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Regeneration is a key goal in the design of immunosensors. In this study, we report the temperature-regulated interaction of N-isopropylacrylamide (PNIPAAm) functionalised cardiac troponin T (cTnT) with anti-cTnT. Covalently bonded PNIPAAm on an anti-cTnT bioelectrode showed on/off-switchability, regeneration capacity and temperature triggered sensitivity for cTnT. Above the lower critical solution temperature (LCST), PNIPAAm provides a liphophilic microenvironment with specific volume reduction at the bioelectrode surface, making available binding space for cTnT, and facilitating analyte recognition. Computational studies provide details about the structural changes occurring at the electrode above and below the LCST. Furthermore, free energies associated with the binding of cTnT with PNIPAAm at 25 (Delta G(coil)=-6.0 Kcal/mole) and 37 degrees C (Delta G(globular)=-41.0 kcal/mole) were calculated to elucidate the interaction and stability of the antigen-antibody complex. The responsiveness of such assemblies opens the way for miniaturised, smart immuno-technologies with built-in programmable interactions of antigen-antibody upon receiving stimuli.

  • 24.
    Asif, Muhammad
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan. COMSATS institute of Information Technology, Lahore, Pakistan.
    Elinder, Fredrik
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Electrochemical Biosensors Based on ZnO Nanostructures to Measure Intracellular Metal Ions and Glucose2011Inngår i: Journal of Analytical & Bioanalytical Techniques, ISSN 2155-9872, Vol. S7, nr 003, s. 1-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Zinc oxide (ZnO) nanostructures have attracted much interest for intracellular electrochemical measurements because of its large surface area, and its biocompatible properties. To design intracellular biosensors for metal ions and glucose, we grew ZnO nanorods on the tip of borosilicate glass capillaries (0.7μm in diameter) and characterized the nano-scale structure with field-emission scanning electron microscopy and high-resolution transmission electron microscopy. The ZnO nanorods were functionalized accordingly for intracellular free metal ions or glucose measurements. Selectivity was achieved by using a metal-ion selective plastic membrane or glucose oxidase enzyme for glucose measurements. These functionalized ZnO nanorods showed high sensitivity and good biocompatibility for intracellular environments. Human adipocytes and frog oocytes were used for determinations of intracellular free metal ions and glucose concentrations. In this review, we discuss the simple and direct approach for intracellular measurements using ZnO nanostructure-based potentiometric biosensors for clinical and non-clinical applications. The performance of ZnO nanostructure-based intracellular sensor can be improved through engineering of morphology, effective surface area, functionality, and adsorption/desorption capability. This study paves the way to find applications in biomedicine by using this simple and miniaturized biosensing device

  • 25.
    Askari, Sadegh
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. Christian Albrechts Univ Kiel, Germany.
    Machhadani, Houssaine
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Benedikt, J.
    Christian Albrechts Univ Kiel, Germany.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Plasma-based processes for planar and 3D surface patterning of functional nanoparticles2019Inngår i: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 21, nr 11, artikkel-id 223Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a gas-phase process for surface patterning and 3D self-assembly of nanoparticles (NPs) of functional materials such as metals, oxides, and nitrides. The method relies on electrostatic assembly of free-flying NPs with unipolar charge produced in plasma sources. We demonstrate the capability of the process in self-assembly of NPs, with the size in the range 10-60 nm, into arrays of free-standing 3D microstructures with complex morphologies. Considering that the plasma nanoparticle sources are compatible with synthesis of a large library of material NPs, the process introduces a novel approach for 3D printing of various functional NPs, high-precision device integration of NPs on sub-micrometer scales, and large-area parallel surface patterning of NPs.

    Fulltekst (pdf)
    fulltext
  • 26.
    Askari, Sadegh
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. Christian Albrechts Univ Kiel, Germany.
    Mariotti, Davide
    Ulster Univ, North Ireland.
    Stehr, Jan Eric
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Benedikt, Jan
    Christian Albrechts Univ Kiel, Germany.
    Keraudy, Julien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Low-Loss and Tunable Localized Mid-Infrared Plasmons in Nanocrystals of Highly Degenerate InN2018Inngår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 18, nr 9, s. 5681-5687Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Plasmonic response of free charges confined in nanostructures of plasmonic materials is a powerful means for manipulating the light-material interaction at the nanoscale and hence has influence on various relevant technologies. In particular, plasmonic materials responsive in the mid-infrared range are technologically important as the mid-infrared is home to the vibrational resonance of molecules and also thermal radiation of hot objects. However, the development of the field is practically challenged with the lack of low-loss materials supporting high quality plasmons in this range of the spectrum. Here, we demonstrate that degenerately doped InN nanocrystals (NCs) support tunable and low-loss plasmon resonance spanning the entire midwave infrared range. Modulating free-carrier concentration is achieved by engineering nitrogen-vacancy defects (InN1-x, 0.017 amp;lt; x amp;lt; 0.085) in highly degenerate NCs using a nonequilibrium gas-phase growth process. Despite the significant reduction in the carrier mobility relative to intrinsic InN, the mobility in degenerate InN NCs (amp;gt;60 cm(2)/(V s)) remains considerably higher than the carrier mobility reported for other materials NCs such as doped metal oxides, chalcogenides, and noble metals. These findings demonstrate feasibility of controlled tuning of infrared plasmon resonances in a low-loss material of III-V compounds and open a gateway to further studies of these materials nanostructures for infrared plasmonic applications.

    Fulltekst (pdf)
    fulltext
  • 27.
    Atakan, Aylin
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Mäkie, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Söderlind, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Keraudy, Julien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Johansson, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Synthesis of a Cu-infiltrated Zr-doped SBA-15 catalyst for CO2 hydrogenation into methanol and dimethyl ethert2017Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 29, s. 19139-19149Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A catalytically active nanoassembly comprising Cu-nanoparticles grown on integrated and active supports (large pore Zr-doped mesoporous SBA-15 silica) has been synthesized and used to promote CO2 hydrogenation. The doped mesoporous material was synthesized using a sal-gel method, in which the pore size was tuned between 11 and 15 nm while maintaining a specific surface area of about 700 m(2) g (1). The subsequent Cu nanoparticle growth was achieved by an infiltration process involving attachment of different functional groups on the external and internal surfaces of the mesoporous structure such that 7-10 nm sized Cu nanoparticles grew preferentially inside the pores. Chemisorption showed improved absorption of both CO2 and H-2 for the assembly compared to pure SBA-15 and 15% of the total CO2 was converted to methanol and dimethyl ether at 250 degrees C and 33 bar.

  • 28.
    Atif, M.
    et al.
    King Saud Univ, Saudi Arabia.
    Ait Ali, Abderrahman
    COMSATS Inst Informat Technol, Pakistan.
    AlSalhi, M. S.
    King Saud Univ, Saudi Arabia.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Effect of Urea on the Morphology of Fe3O4 Magnetic Nanoparticles and Their Application in Potentiometric Urea Biosensors2019Inngår i: Silicon, ISSN 1876-990X, E-ISSN 1876-9918, Vol. 11, nr 3, s. 1371-1376Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of different concentrations of urea on the morphology of iron oxide (Fe3O4) magnetic nanoparticles was studied. Fe3O4 magnetic nanoparticles were fabricated by the coprecipitation method. The morphology, crystallinity, compositional purity, and emission characteristics were tested by the techniques of scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and Raman characterization. The drop-casting technique was successfully used to fabricate a potentiometric urea biosensor producing initially isopropanol and chitosan solution, consisting of Fe3O4 nanoparticles, on a glass fiber filter. To measure the developed biosensors voltage signal from the functionalized nanoparticles, a copper wire was utilized. The Fe3O4 nanoparticle surface functionalization was performed through the electrostatic immobilization of urease with the Fe3O4-chitosan (CH) nanobiocomposite. The presented urea biosensor measured a wide logarithmic range of urea concentration of 0.1-80 mM with a sensitivity of 42 mV/decade, and indicated a fast response time of approximately 12 s. The developed urea biosensor showed enhanced sensitivity, stability, reusability, and specificity. All experimental results demonstrate the application potential of the developed urea sensor for the monitoring of urea concentrations in human serum, drugs, and food industry-related samples.

  • 29.
    Ayedh, Hussein M.
    et al.
    University of Oslo, Department of Physics, Center for Materials Science and Nanotechnology, N-0316 Oslo, NORWAY .
    Baathen, Marianne E.
    University of Oslo, Department of Physics, Center for Materials Science and Nanotechnology, N-0316 Oslo, NORWAY .
    Galeckas, Augustinas
    University of Oslo, Department of Physics, Center for Materials Science and Nanotechnology, N-0316 Oslo, NORWAY .
    ul-Hassan, Jawad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Bergman, Peder
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Nipoti, Roberta
    CNR-IMM of Bologna, I-40129 Bologna, ITALY.
    Hallen, Anders
    Royal Institute of Technology, KTH, School of Information and Communication Technology, SE-164 40 Kista-Stockholm, SWEDEN.
    Svensson, Bengt G
    University of Oslo, Department of Physics, Center for Materials Science and Nanotechnology, N-0316 Oslo, NORWAY.
    (Invited) Controlling the Carbon Vacancy in 4H-SiC by Thermal Processing2018Inngår i: ECS Transactions, ISSN 1938-5862, E-ISSN 1938-6737, ECS Transactions, Vol. 86, nr 12, s. 91-97Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The carbon vacancy (VC) is perhaps the most prominent point defect in silicon carbide (SiC) and it is an efficient charge carrier lifetime killer in high-purity epitaxial layers of 4H-SiC. The VC concentration needs to be controlled and minimized for optimum materials and device performance, and an approach based on post-growth thermal processing under C-rich ambient conditions is presented. It utilizes thermodynamic equilibration and after heat treatment at 1500 °C for 1 h, the VC concentration is shown to be reduced by a factor ~25 relative to that in as-grown state-of-the-art epi-layers. Concurrently, a considerable enhancement of the carrier lifetime occurs throughout the whole of >40 µm thick epi-layers.

  • 30.
    Aziz, Shazed
    et al.
    Department of Chemical and Environmental Engineering, Faculty of Engineering, University Putra Malaysia, Selangor, Malaysia.
    Rashid, Suraya
    Department of Chemical and Environmental Engineering, Faculty of Engineering, University Putra Malaysia, Selangor, Malaysia; Advanced Materials and Nanotechnology Lab , Institute of Advanced Technology, University Putra Malaysia, Selangor, Malaysia.
    Salleh, Mohamad Amran Mohd
    Department of Chemical and Environmental Engineering, Faculty of Engineering, University Putra Malaysia, Selangor, Malaysia; Advanced Materials and Nanotechnology Lab, Institute of Advanced Technology, University Putra Malaysia, Selangor, Malaysia.
    Theoretical Prediction of CNT-CF/PP Composite Tensile Properties Using Various Numerical Modeling Methods2013Inngår i: Fullerenes, nanotubes, and carbon nanostructures (Print), ISSN 1536-383X, E-ISSN 1536-4046, Vol. 21, nr 5, s. 411-416Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Development of effective models to predict tensile properties of ‘carbon nanotube coated carbon fibre reinforced polypropylene (CNT-CF/PP)’ composites is briefly discussed. The composite taken as the reference is based on the highest growth mechanism of CNTs over carbon fibres. Halpin-Tsai and Combined Voigt-Reuss model has been implemented. Young's modulus for CNT-CF/PP composites has been found 4.5368 GPa and the tensile strength has been estimated 45.367 MPa considering the optimum operating condition of chemical vapor deposition (CVD) technique. Stiffness of the composite is represented through the stress-strain plots; stiffness is proportional to the steepness of the slope. There are slight deviations of results that have been found theoretically over the experimental issues.

  • 31.
    Backes, Claudia
    et al.
    Heidelberg Univ, Germany; Trinity Coll Dublin, Ireland; Trinity Coll Dublin, Ireland.
    Abdelkader, Amr M.
    Univ Cambridge, England.
    Alonso, Concepcion
    Autonomous Univ Madrid, Spain.
    Andrieux-Ledier, Amandine
    Univ Paris Saclay, France.
    Arenal, Raul
    ARAID Fundat, Spain; Univ Zaragoza, Spain; Univ Zaragoza, Spain.
    Azpeitia, Jon
    CSIC, Spain.
    Balakrishnan, Nilanthy
    Univ Nottingham, England.
    Banszerus, Luca
    Rhein Westfal TH Aachen, Germany; Rhein Westfal TH Aachen, Germany.
    Barjon, Julien
    Univ Paris Saclay, France.
    Bartali, Ruben
    Fdn Bruno Kessler, Italy.
    Bellani, Sebastiano
    Ist Italiano Tecnol, Italy.
    Berger, Claire
    Univ Grenoble Alpes, France; Georgia Inst Technol, GA 30332 USA.
    Berger, Reinhard
    Tech Univ Dresden, Germany; Tech Univ Dresden, Germany.
    Ortega, M. M. Bernal
    Politecn Torino, Italy.
    Bernard, Carlo
    Univ Zurich, Switzerland.
    Beton, Peter H.
    Univ Nottingham, England.
    Beyer, Andre
    Bielefeld Univ, Germany.
    Bianco, Alberto
    Univ Strasbourg, France.
    Boggild, Peter
    Tech Univ Denmark, Denmark.
    Bonaccorso, Francesco
    Ist Italiano Tecnol, Italy; BeDimens Spa, Italy.
    Barin, Gabriela Borin
    Empa, Switzerland.
    Botas, Cristina
    CIC EnergiGUNE, Spain.
    Bueno, Rebeca A.
    CSIC, Spain.
    Carriazo, Daniel
    CIC EnergiGUNE, Spain; Basque Fdn Sci, Spain.
    Castellanos-Gomez, Andres
    CSIC, Spain.
    Christian, Meganne
    CNR, Italy.
    Ciesielski, Artur
    Univ Strasbourg, France.
    Ciuk, Tymoteusz
    Inst Technol Mat Elekt, Poland.
    Cole, Matthew T.
    Dept Elect and Elect Engn, England.
    Coleman, Jonathan
    Trinity Coll Dublin, Ireland; Trinity Coll Dublin, Ireland.
    Coletti, Camilla
    Ist Italiano Tecnol, Italy; Ist Italiano Tecnol, Italy.
    Crema, Luigi
    Fdn Bruno Kessler, Italy.
    Cun, Huanyao
    Univ Zurich, Switzerland.
    Dasler, Daniela
    Friedrich Alexander Univ Erlangen Nurnberg, Germany; Friedrich Alexander Univ Erlangen Nurnberg, Germany.
    De Fazio, Domenico
    Univ Cambridge, England.
    Diez, Noel
    CIC EnergiGUNE, Spain.
    Drieschner, Simon
    Univ Munich, Germany.
    Duesberg, Georg S.
    Univ Bundeswehr Munchen, Germany.
    Fasel, Roman
    Empa, Switzerland; Univ Bern, Switzerland.
    Feng, Xinliang
    Tech Univ Dresden, Germany; Tech Univ Dresden, Germany.
    Fina, Alberto
    Politecn Torino, Italy.
    Forti, Stiven
    Ist Italiano Tecnol, Italy.
    Galiotis, Costas
    Univ Patras, Greece; Fdn Res and Technol Hellas FORTH ICE HT, Greece.
    Garberoglio, Giovanni
    European Ctr Theoret Studies Nucl Phys and Related, Italy; INFN, Italy.
    Garcia, Jorge M.
    CSIC, Spain.
    Antonio Garrido, Jose
    Inst Catalan Nanotecnol ICN2, Spain.
    Gibertini, Marco
    Ecole Polytech Fed Lausanne, Switzerland; Ecole Polytech Fed Lausanne, Switzerland.
    Goelzhaeuser, Armin
    Bielefeld Univ, Germany.
    Gomez, Julio
    Avanzare Innovac Tecnol SL, Spain.
    Greber, Thomas
    Univ Zurich, Switzerland.
    Hauke, Frank
    Friedrich Alexander Univ Erlangen Nurnberg, Germany; Friedrich Alexander Univ Erlangen Nurnberg, Germany.
    Hemmi, Adrian
    Univ Zurich, Switzerland.
    Hernandez-Rodriguez, Irene
    CSIC, Spain.
    Hirsch, Andreas
    Friedrich Alexander Univ Erlangen Nurnberg, Germany; Friedrich Alexander Univ Erlangen Nurnberg, Germany.
    Hodge, Stephen A.
    Univ Cambridge, England.
    Huttel, Yves
    CSIC, Spain.
    Jepsen, Peter U.
    Tech Univ Denmark, Denmark.
    Jimenez, Ignacio
    CSIC, Spain.
    Kaiser, Ute
    Univ Ulm, Germany.
    Kaplas, Tommi
    Univ Eastern Finland, Finland.
    Kim, HoKwon
    Ecole Polytech Fed Lausanne, Switzerland; Ecole Polytech Fed Lausanne, Switzerland.
    Kis, Andras
    Ecole Polytech Fed Lausanne, Switzerland; Ecole Polytech Fed Lausanne, Switzerland.
    Papagelis, Konstantinos
    Fdn Res and Technol Hellas FORTH ICE HT, Greece; Aristotle Univ Thessaloniki, Greece.
    Kostarelos, Kostas
    Univ Manchester, England.
    Krajewska, Aleksandra
    Inst Technol Mat Elekt, Poland; Polish Acad Sci, Poland.
    Lee, Kangho
    Univ Bundeswehr Munchen, Germany.
    Li, Changfeng
    Aalto Univ, Finland.
    Lipsanen, Harri
    Aalto Univ, Finland.
    Liscio, Andrea
    CNR, Italy.
    Lohe, Martin R.
    Tech Univ Dresden, Germany; Tech Univ Dresden, Germany.
    Loiseau, Annick
    Univ Paris Saclay, France.
    Lombardi, Lucia
    Univ Cambridge, England.
    Francisca Lopez, Maria
    CSIC, Spain.
    Martin, Oliver
    Friedrich Alexander Univ Erlangen Nurnberg, Germany; Friedrich Alexander Univ Erlangen Nurnberg, Germany.
    Martin, Cristina
    Univ Castilla La Mancha, Spain.
    Martinez, Lidia
    CSIC, Spain.
    Angel Martin-Gago, Jose
    CSIC, Spain.
    Ignacio Martinez, Jose
    CSIC, Spain.
    Marzari, Nicola
    Ecole Polytech Fed Lausanne, Switzerland; Ecole Polytech Fed Lausanne, Switzerland.
    Mayoral, Alvaro
    Univ Zaragoza, Spain; ShanghaiTech Univ, Peoples R China.
    McManus, John
    Trinity Coll Dublin, Ireland; Trinity Coll Dublin, Ireland.
    Melucci, Manuela
    CNR, Italy.
    Mendez, Javier
    CSIC, Spain.
    Merino, Cesar
    Grp Antolin Ingn SA, Spain.
    Merino, Pablo
    CSIC, Spain; CSIC, Spain.
    Meyer, Andreas P.
    Friedrich Alexander Univ Erlangen Nurnberg, Germany; Friedrich Alexander Univ Erlangen Nurnberg, Germany.
    Miniussi, Elisa
    Univ Zurich, Switzerland.
    Miseikis, Vaidotas
    Ist Italiano Tecnol, Italy.
    Mishra, Neeraj
    Ist Italiano Tecnol, Italy.
    Morandi, Vittorio
    CNR, Italy.
    Munuera, Carmen
    CSIC, Spain.
    Munoz, Roberto
    CSIC, Spain.
    Nolan, Hugo
    Trinity Coll Dublin, Ireland; Trinity Coll Dublin, Ireland.
    Ortolani, Luca
    CNR, Italy.
    Ott, Anna K.
    Univ Cambridge, England; Univ Exeter, England.
    Palacio, Irene
    CSIC, Spain.
    Palermo, Vincenzo
    CNR, Italy; Chalmers Univ Technol, Sweden.
    Parthenios, John
    Fdn Res and Technol Hellas FORTH ICE HT, Greece.
    Pasternak, Iwona
    Inst Technol Mat Elekt, Poland; Warsaw Univ Technol, Poland.
    Patane, Amalia
    Univ Nottingham, England.
    Prato, Maurizio
    Basque Fdn Sci, Spain; CIC BiomaGUNE, Spain; Univ Trieste, Italy.
    Prevost, Henri
    Univ Paris Saclay, France.
    Prudkovskiy, Vladimir
    Univ Grenoble Alpes, France.
    Pugno, Nicola
    Univ Trento, Italy; Edoardo Amaldi Foudat, Italy; Queen Mary Univ London, England.
    Rojo, Teofilo
    CIC EnergiGUNE, Spain; Univ Basque Country, Spain.
    Rossi, Antonio
    Ist Italiano Tecnol, Italy.
    Ruffieux, Pascal
    Empa, Switzerland.
    Samori, Paolo
    Univ Strasbourg, France.
    Schue, Leonard
    Univ Paris Saclay, France.
    Setijadi, Eki
    Fdn Bruno Kessler, Italy.
    Seyller, Thomas
    Tech Univ Chemnitz, Germany.
    Speranza, Giorgio
    Fdn Bruno Kessler, Italy.
    Stampfer, Christoph
    Rhein Westfal TH Aachen, Germany; Rhein Westfal TH Aachen, Germany.
    Stenger, Ingrid
    Univ Paris Saclay, France.
    Strupinski, Wlodek
    Inst Technol Mat Elekt, Poland; Warsaw Univ Technol, Poland.
    Svirko, Yuri
    Univ Eastern Finland, Finland.
    Taioli, Simone
    European Ctr Theoret Studies Nucl Phys and Related, Italy; INFN, Italy; Charles Univ Prague, Czech Republic.
    Teo, Kenneth B. K.
    Buckingway Business Pk, England.
    Testi, Matteo
    Fdn Bruno Kessler, Italy.
    Tomarchio, Flavia
    Univ Cambridge, England.
    Tortello, Mauro
    Politecn Torino, Italy.
    Treossi, Emanuele
    CNR, Italy.
    Turchanin, Andrey
    Friedrich Schiller Univ Jena, Germany.
    Vazquez, Ester
    Univ Castilla La Mancha, Spain.
    Villaro, Elvira
    Interquimica, Spain.
    Whelan, Patrick R.
    Tech Univ Denmark, Denmark.
    Xia, Zhenyuan
    CNR, Italy; Chalmers Univ Technol, Sweden.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Yang, Sheng
    Tech Univ Dresden, Germany; Tech Univ Dresden, Germany.
    Reza Yazdi, G.
    Not Found:Univ Linkoping, IFM, S-58183 Linkoping, Sweden.
    Yim, Chanyoung
    Univ Bundeswehr Munchen, Germany.
    Yoon, Duhee
    Univ Cambridge, England.
    Zhang, Xianghui
    Bielefeld Univ, Germany.
    Zhuang, Xiaodong
    Tech Univ Dresden, Germany; Tech Univ Dresden, Germany.
    Colombo, Luigi
    Univ Texas Dallas, TX 75080 USA.
    Ferrari, Andrea C.
    Univ Cambridge, England.
    Garcia-Hernandez, Mar
    CSIC, Spain.
    Production and processing of graphene and related materials2020Inngår i: 2D MATERIALS, ISSN 2053-1583, Vol. 7, nr 2, artikkel-id 022001Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    We present an overview of the main techniques for production and processing of graphene and related materials (GRMs), as well as the key characterization procedures. We adopt a hands-on approach, providing practical details and procedures as derived from literature as well as from the authors experience, in order to enable the reader to reproduce the results. Section I is devoted to bottom up approaches, whereby individual constituents are pieced together into more complex structures. We consider graphene nanoribbons (GNRs) produced either by solution processing or by on-surface synthesis in ultra high vacuum (UHV), as well carbon nanomembranes (CNM). Production of a variety of GNRs with tailored band gaps and edge shapes is now possible. CNMs can be tuned in terms of porosity, crystallinity and electronic behaviour. Section II covers top down techniques. These rely on breaking down of a layered precursor, in the graphene case usually natural crystals like graphite or artificially synthesized materials, such as highly oriented pyrolythic graphite, monolayers or few layers (FL) flakes. The main focus of this section is on various exfoliation techniques in a liquid media, either intercalation or liquid phase exfoliation (LPE). The choice of precursor, exfoliation method, medium as well as the control of parameters such as time or temperature are crucial. A definite choice of parameters and conditions yields a particular material with specific properties that makes it more suitable for a targeted application. We cover protocols for the graphitic precursors to graphene oxide (GO). This is an important material for a range of applications in biomedicine, energy storage, nanocomposites, etc. Hummers and modified Hummers methods are used to make GO that subsequently can be reduced to obtain reduced graphene oxide (RGO) with a variety of strategies. GO flakes are also employed to prepare three-dimensional (3d) low density structures, such as sponges, foams, hydro- or aerogels. The assembly of flakes into 3d structures can provide improved mechanical properties. Aerogels with a highly open structure, with interconnected hierarchical pores, can enhance the accessibility to the whole surface area, as relevant for a number of applications, such as energy storage. The main recipes to yield graphite intercalation compounds (GICs) are also discussed. GICs are suitable precursors for covalent functionalization of graphene, but can also be used for the synthesis of uncharged graphene in solution. Degradation of the molecules intercalated in GICs can be triggered by high temperature treatment or microwave irradiation, creating a gas pressure surge in graphite and exfoliation. Electrochemical exfoliation by applying a voltage in an electrolyte to a graphite electrode can be tuned by varying precursors, electrolytes and potential. Graphite electrodes can be either negatively or positively intercalated to obtain GICs that are subsequently exfoliated. We also discuss the materials that can be amenable to exfoliation, by employing a theoretical data-mining approach. The exfoliation of LMs usually results in a heterogeneous dispersion of flakes with different lateral size and thickness. This is a critical bottleneck for applications, and hinders the full exploitation of GRMs produced by solution processing. The establishment of procedures to control the morphological properties of exfoliated GRMs, which also need to be industrially scalable, is one of the key needs. Section III deals with the processing of flakes. (Ultra)centrifugation techniques have thus far been the most investigated to sort GRMs following ultrasonication, shear mixing, ball milling, microfluidization, and wet-jet milling. It allows sorting by size and thickness. Inks formulated from GRM dispersions can be printed using a number of processes, from inkjet to screen printing. Each technique has specific rheological requirements, as well as geometrical constraints. The solvent choice is critical, not only for the GRM stability, but also in terms of optimizing printing on different substrates, such as glass, Si, plastic, paper, etc, all with different surface energies. Chemical modifications of such substrates is also a key step. Sections IV-VII are devoted to the growth of GRMs on various substrates and their processing after growth to place them on the surface of choice for specific applications. The substrate for graphene growth is a key determinant of the nature and quality of the resultant film. The lattice mismatch between graphene and substrate influences the resulting crystallinity. Growth on insulators, such as SiO2, typically results in films with small crystallites, whereas growth on the close-packed surfaces of metals yields highly crystalline films. Section IV outlines the growth of graphene on SiC substrates. This satisfies the requirements for electronic applications, with well-defined graphene-substrate interface, low trapped impurities and no need for transfer. It also allows graphene structures and devices to be measured directly on the growth substrate. The flatness of the substrate results in graphene with minimal strain and ripples on large areas, allowing spectroscopies and surface science to be performed. We also discuss the surface engineering by intercalation of the resulting graphene, its integration with Si-wafers and the production of nanostructures with the desired shape, with no need for patterning. Section V deals with chemical vapour deposition (CVD) onto various transition metals and on insulators. Growth on Ni results in graphitized polycrystalline films. While the thickness of these films can be optimized by controlling the deposition parameters, such as the type of hydrocarbon precursor and temperature, it is difficult to attain single layer graphene (SLG) across large areas, owing to the simultaneous nucleation/growth and solution/precipitation mechanisms. The differing characteristics of polycrystalline Ni films facilitate the growth of graphitic layers at different rates, resulting in regions with differing numbers of graphitic layers. High-quality films can be grown on Cu. Cu is available in a variety of shapes and forms, such as foils, bulks, foams, thin films on other materials and powders, making it attractive for industrial production of large area graphene films. The push to use CVD graphene in applications has also triggered a research line for the direct growth on insulators. The quality of the resulting films is lower than possible to date on metals, but enough, in terms of transmittance and resistivity, for many applications as described in section V. Transfer technologies are the focus of section VI. CVD synthesis of graphene on metals and bottom up molecular approaches require SLG to be transferred to the final target substrates. To have technological impact, the advances in production of high-quality large-area CVD graphene must be commensurate with those on transfer and placement on the final substrates. This is a prerequisite for most applications, such as touch panels, anticorrosion coatings, transparent electrodes and gas sensors etc. New strategies have improved the transferred graphene quality, making CVD graphene a feasible option for CMOS foundries. Methods based on complete etching of the metal substrate in suitable etchants, typically iron chloride, ammonium persulfate, or hydrogen chloride although reliable, are time- and resource-consuming, with damage to graphene and production of metal and etchant residues. Electrochemical delamination in a low-concentration aqueous solution is an alternative. In this case metallic substrates can be reused. Dry transfer is less detrimental for the SLG quality, enabling a deterministic transfer. There is a large range of layered materials (LMs) beyond graphite. Only few of them have been already exfoliated and fully characterized. Section VII deals with the growth of some of these materials. Amongst them, h-BN, transition metal tri- and di-chalcogenides are of paramount importance. The growth of h-BN is at present considered essential for the development of graphene in (opto) electronic applications, as h-BN is ideal as capping layer or substrate. The interesting optical and electronic properties of TMDs also require the development of scalable methods for their production. Large scale growth using chemical/physical vapour deposition or thermal assisted conversion has been thus far limited to a small set, such as h-BN or some TMDs. Heterostructures could also be directly grown. Section VIII discusses advances in GRM functionalization. A broad range of organic molecules can be anchored to the sp(2) basal plane by reductive functionalization. Negatively charged graphene can be prepared in liquid phase (e.g. via intercalation chemistry or electrochemically) and can react with electrophiles. This can be achieved both in dispersion or on substrate. The functional groups of GO can be further derivatized. Graphene can also be noncovalently functionalized, in particular with polycyclic aromatic hydrocarbons that assemble on the sp(2) carbon network by pi-pi stacking. In the liquid phase, this can enhance the colloidal stability of SLG/FLG. Approaches to achieve noncovalent on-substrate functionalization are also discussed, which can chemically dope graphene. Research efforts to derivatize CNMs are also summarized, as well as novel routes to selectively address defect sites. In dispersion, edges are the most dominant defects and can be covalently modified. This enhances colloidal stability without modifying the graphene basal plane. Basal plane point defects can also be modified, passivated and healed in ultra-high vacuum. The decoration of graphene with metal nanoparticles (NPs) has also received considerable attention, as it allows to exploit synergistic effects between NPs and graphene. Decoration can be either achieved chemically or in the gas phase. All LMs, can be functionalized and we summarize emerging approaches to covalently and noncovalently functionalize MoS2 both in the liquid and on substrate. Section IX describes some of the most popular characterization techniques, ranging from optical detection to the measurement of the electronic structure. Microscopies play an important role, although macroscopic techniques are also used for the measurement of the properties of these materials and their devices. Raman spectroscopy is paramount for GRMs, while PL is more adequate for non-graphene LMs (see section IX.2). Liquid based methods result in flakes with different thicknesses and dimensions. The qualification of size and thickness can be achieved using imaging techniques, like scanning probe microscopy (SPM) or transmission electron microscopy (TEM) or spectroscopic techniques. Optical microscopy enables the detection of flakes on suitable surfaces as well as the measurement of optical properties. Characterization of exfoliated materials is essential to improve the GRM metrology for applications and quality control. For grown GRMs, SPM can be used to probe morphological properties, as well as to study growth mechanisms and quality of transfer. More generally, SPM combined with smart measurement protocols in various modes allows one to get obtain information on mechanical properties, surface potential, work functions, electrical properties, or effectiveness of functionalization. Some of the techniques described are suitable for in situ characterization, and can be hosted within the growth chambers. If the diagnosis is made ex situ, consideration should be given to the preparation of the samples to avoid contamination. Occasionally cleaning methods have to be used prior to measurement.

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  • 32.
    Bai, Jianhao
    et al.
    National University of Singapore.
    Beyer, Sebastian
    National University of Singapore.
    Mak, Wing Cheung
    Hong Kong University of Science and Technology, Hong Kong, China .
    Trau, Dieter
    National University of Singapore.
    Fabrication of inflated LbL microcapsules with a ‘bead-in-a-capsule’ morphology2009Inngår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 5, s. 4152-4160Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The fabrication of inflated Layer-by-Layer (LbL) microcapsules with a unique ‘bead-in-a-capsule’ morphology is presented. Currently, the fabrication of LbL microcapsules using conventional aqueous LbL techniques usually results in microcapsules with a two-phase system (LbL capsular wall with an air, liquid, solid or hydrogel core). Here, we present the fabrication of inflated LbL microcapsules with a unique three-phase system (LbL capsular wall, hydrogel microbead in an aqueous core) by using the Reverse-Phase LbL (RP-LbL) technique. The RP-LbL technique is performed in an organic solvent and allows encapsulation of water-soluble templates and molecules with high efficiency. Firstly, the RP-LbL technique is used to coat polymer layers onto agarose microbeads containing TRIS buffer for the formation of LbL capsular walls onto the microbeads and to minimize out-diffusion of encapsulated TRIS. Next, the polymer-coated agarose microbeads are transferred from an organic to an aqueous solvent where the TRIS molecules induce an osmotic pressure in the microcapsules' interior. This pressure drives the inflation of the LbL microcapsules that causes the expansion of the LbL capsular walls. Fluorescence staining reveals that the inflated LbL microcapsules consist of an agarose microbead suspended within the aqueous interior of the capsule but still attached to the LbL capsular wall at one point; thereby displaying a ‘bead-in-a-capsule’ morphology. It was demonstrated that the degree of inflation depends on the concentration of pre-loaded TRIS and the number of coated polymer layers. Also, ADOGEN® 464 (a cationic surfactant) is required for the fabrication of the inflated LbL microcapsules. The mass of dextran macromolecules (65–2000 kDa) diffusing through the LbL capsular wall had decreased by at least 49% after expansion of the capsular wall. Inflated microcapsules were shown to be capable of controlling the distribution of two different materials internally. Hence, it is possible that inflated microcapsules can permit localized control over chemical or enzymatic reactions for future uses in biomedical applications.

  • 33.
    Bai, Sai
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yuan, Zhongcheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Colloidal metal halide perovskite nanocrystals: synthesis, characterization, and applications2016Inngår i: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 4, nr 18, s. 3898-3904Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Colloidal metal halide perovskite nanocrystals (NCs) have emerged as promising materials for optoelectronic devices and received considerable attention recently. Their superior photoluminescence (PL) properties provide significant advantages for lighting and display applications. In this Highlight, we discuss recent developments in the design and chemical synthesis of colloidal perovskite NCs, including both organic-inorganic hybrid and all inorganic perovskite NCs. We review the excellent PL properties and current optoelectronic applications of these perovskite NCs. In addition, critical challenges that currently limit the applicability of perovskite NCs are discussed, and prospects for future directions are proposed.

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  • 34.
    Battocchio, Chiara
    et al.
    Roma Tre Univ, Italy.
    Concolato, Sofia
    Roma Tre Univ, Italy.
    De Santis, Serena
    Roma Tre Univ, Italy.
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Iucci, Giovanna
    Roma Tre Univ, Italy.
    Santi, Marta
    Roma Tre Univ, Italy.
    Sotgiu, Giovanni
    Roma Tre Univ, Italy.
    Orsini, Monica
    Roma Tre Univ, Italy.
    Chitosan functionalization of titanium and Ti6Al4V alloy with chloroacetic acid as linker agent2019Inngår i: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 99, s. 1133-1140Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, a new covalent grafting of chitosan on titanium and Ti6Al4V alloy surfaces is reported using chloroacetic acid as linker agent. Good results were obtained both on titanium and on Ti6Al4V alloy. The effect of the surface acid pretreatments on the subsequent functionalization with chitosan is evaluated. The morphological aspect of acid etched metal surfaces before chitosan grafting has been characterized by scanning electron microscopy (SEM). The presence of carboxylic groups on metal surfaces and then the efficiency of chitosan covalent immobilization were detected by Fourier transformed infrared-Attenuated Total Reflectance (FTIR-ATR) and X-Ray photoelectron spectroscopy (XPS). Cyclic voltammetry tests, using the functionalized titanium and Ti6Al4V samples as electrodes, were conducted in different aqueous solutions, to detect the presence of the homogeneous overlayer of chitosan on the surface, and to evaluate the importance of the carboxyl groups as linker agent.

  • 35.
    Belaineh, Dagmawi
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Andreasen, Jens W.
    Tech Univ Denmark, Denmark.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Malti, Abdellah
    KTH Royal Inst Technol, Sweden; KTH Royal Inst Technol, Sweden.
    Håkansson, Karl
    RISE Bioecon, Sweden.
    Wagberg, Lars
    KTH Royal Inst Technol, Sweden; KTH Royal Inst Technol, Sweden.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Engquist, Isak
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Controlling the Organization of PEDOT:PSS on Cellulose Structures2019Inngår i: ACS APPLIED POLYMER MATERIALS, ISSN 2637-6105, Vol. 1, nr 9, s. 2342-2351Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Composites of biopolymers and conducting polymers are emerging as promising candidates for a green technological future and are actively being explored in various applications, such as in energy storage, bioelectronics, and thermoelectrics. While the device characteristics of these composites have been actively investigated, there is limited knowledge concerning the fundamental intracomponent interactions and the modes of molecular structuring. Here, by use of cellulose and poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), it is shown that the chemical and structural makeup of the surfaces of the composite components are critical factors that determine the materials organization at relevant dimensions. AFM, TEM, and GIVVAXS measurements show that when mixed with cellulose nanofibrils, PEDOT:PSS organizes into continuous nanosized beadlike structures with an average diameter of 13 nm on the nanofibrils. In contrast, when PEDOT:PSS is blended with molecular cellulose, a phase-segregated conducting network morphology is reached, with a distinctly relatively lower electric conductivity. These results provide insight into the mechanisms of PEDOT:PSS crystallization and may have significant implications for the design of conducting biopolymer composites for a vast array of applications.

    Fulltekst tilgjengelig fra 2020-07-22 13:05
  • 36. Bestill onlineKjøp publikasjonen >>
    Bengtsson, Katarina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Electrokinetic devices from polymeric materials2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    There are multiple applications for polymers: our bodies are built of them, plastic bags and boxes used for storage are composed of them, as are the shells for electronics, TVs, computers, clothes etc. Many polymers are cheap, and easy to manufacture and process which make them suitable for disposable systems. The choice of polymer to construct an object will therefore highly influence the properties of the object itself. The focus of this thesis is the application of commonly used polymers to solve some challenges regarding integration of electrodes in electrokinetic devices and 3D printing.

    The first part of this thesis regards electrokinetic systems and the electrodes’ impact on the system. Electrokinetic systems require Faradaic (electrochemical) reactions at the electrodes to maintain an electric field in an electrolyte. The electrochemical reactions at the electrodes allow electron-to-ion transduction at the electrode-electrolyte interface, necessary to drive a current at the applied potential through the system, which thereby either cause flow (electroosmosis) or separation (electrophoresis). These electrochemical reactions at the electrodes, such as water electrolysis, are usually problematic in analytical systems and systems applied in biology. One solution to reduce the impact of water electrolysis is by replacing metal electrodes with electrochemically active polymers, e.g. poly(3,4-ethylenedioxythiophene) (PEDOT). Paper 1 demonstrates that PEDOT electrodes can replace platinum electrodes in a gel electrophoretic setup. Paper 2 reports an all-plastic, planar, flexible electroosmotic pump which continuously transports water from one side to the other using potentials as low as 0.3 V. This electroosmotic pump was further developed in paper 3, where it was made into a compact and modular setup, compatible with commercial microfluidic devices. We demonstrated that the pump could maintain an alternating flow for at least 96 h, with a sufficient flow of cell medium to keep cells alive for the same period of time.

    The second part of the thesis describes the use of 3D printers for manufacturing prototypes and the material requirements for 3D printing. Protruding and over-hanging structures are more challenging to print using a 3D printer and usually require supporting material during the printing process. In paper 4, we showed that polyethylene glycol (PEG), in combination with a carbonate-based plasticizer, functions well as a 3D printable sacrificial template material. PEG2000 with between 20 and 30 wt% dimethyl carbonate or propylene carbonate have good shear-thinning rheology, mechanical and chemical stability, and water solubility, which are advantageous for a supporting material used in 3D printing.

    The advances presented in this thesis have solved some of the challenges regarding electrokinetic systems and prototype manufacturing. Hopefully this will contribute to the development of robust, disposable, low-cost, and autonomous electrokinetic devices.

    Delarbeid
    1. Conducting Polymer Electrodes for Gel Electrophoresis
    Åpne denne publikasjonen i ny fane eller vindu >>Conducting Polymer Electrodes for Gel Electrophoresis
    2014 (engelsk)Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, nr 2, s. 0089416-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that p-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

    sted, utgiver, år, opplag, sider
    Public Library of Science, 2014
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-105901 (URN)10.1371/journal.pone.0089416 (DOI)000331711900141 ()
    Tilgjengelig fra: 2014-04-14 Laget: 2014-04-12 Sist oppdatert: 2017-12-05bibliografisk kontrollert
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  • 37.
    Benselfelt, Tobias
    et al.
    Department of Fiber Technology, KTH, Stockholm, Sweden.
    Nordenström, Malin
    Department of Fiber Technology, KTH, Stockholm, Sweden.
    Lindström, Stefan B
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    Wågberg, Lars
    Department of Fiber Technology, KTH, Stockholm, Sweden.
    Explaining the Exceptional Wet Integrity of Transparent Cellulose Nanofibril Films in the Presence of Multivalent Ions: Suitable Substrates for Biointerfaces2019Inngår i: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 13, nr 6, artikkel-id 1900333Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cellulose nanofibrils (CNFs) assemble into water‐resilient materials in the presence of multivalent counter‐ions. The essential mechanisms behind these assemblies are ion–ion correlation and specific ion effects. A network model shows that the interfibril attraction indirectly influences the wet modulus by a fourth power relationship to the solidity of the network (Ew ∝ φ4). Ions that induce both ion–ion correlation and specific ion effects significantly reduce the swelling of the films, and due to the nonlinear relationship dramatically increase the wet modulus. Herein, this network model is used to explain the elastoplastic behavior of wet films of 2,2,6,6‐tetramethylpiperidine‐1‐oxyl radical (TEMPO)‐oxidized, carboxymethylated, and phosphorylated CNFs in the presence of different counter‐ions. The main findings are that the aspect ratio of the CNFs influences the ductility of the assemblies, that the bivalency of phosphorylate ligands probably limits the formation of interfibril complexes with divalent ions, and that a higher charge density increases the friction between fibrils by increasing the short‐range attraction from ion–ion correlation and specific ion effects. These findings can be used to rationally design CNF materials for a variety of applications where wet strength, ductility, and transparency are important, such as biomaterials or substrates for bioelectronics.

  • 38.
    Bernardin, Evans
    et al.
    University of South Florida, Tampa, FL, U.S.A..
    Frewin, Christopher L.
    University of Texas at Dallas, Dallas, TX, U.S.A.
    Dey, Abhishek
    University of South Florida, Tampa, FL, U.S.A..
    Everly, Richard
    University of South Florida, Tampa, FL, U.S.A..
    Ul Hassan, Jawad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Pancrazio, Joe
    University of Texas at Dallas, Dallas, TX, U.S.A.
    Saddow, Stephen E.
    University of South Florida, Tampa, FL, U.S.A..
    Development of an all-SiC neuronal interface device2016Inngår i: MRS Advances, ISSN 2059-8521, Vol. 1, nr 55, s. 3679-3684Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The intracortical neural interface (INI) is a key component of brain machine interfaces (BMI) which offer the possibility to restore functions lost by patients due to severe trauma to the central or peripheral nervous system. Unfortunately today’s neural electrodes suffer from a variety of design flaws, mainly the use of non-biocompatible materials based on Si or W with polymer coatings to mask the underlying material. Silicon carbide (SiC) is a semiconductor that has been proven to be highly biocompatible, and this chemically inert, physically robust material system may provide the longevity and reliability needed for the INI community. The design, fabrication, and preliminary testing of a prototype all-SiC planar microelectrode array based on 4H-SiC with an amorphous silicon carbide (a-SiC) insulator is described. The fabrication of the planar microelectrode was performed utilizing a series of conventional micromachining steps. Preliminary data is presented which shows a proof of concept for an all-SiC microelectrode device.

  • 39.
    Beyer, Sebastian
    et al.
    Gelsenkirchen University of Applied Sciences, Germany.
    Mak, Wing Cheung
    National University of Singapore.
    Trau, Dieter
    National University of Singapore.
    Reverse-phase LbL-encapsulation of highly water soluble materials by layer-by-layer polyelectrolyte self-assembly2007Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 23, nr 17, s. 8827-8832Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on a novel method for the encapsulation of highly water soluble materials by using layer-by-layer (LbL) polyelectrolyte self-assembly. State of the art polyelectrolyte self-assembly LbL coating and encapsulation methods are only applicable to insoluble or poorly water soluble template materials, because the process is performed in water causing dissolution of the solid template. Our method extends the material spectrum to highly water soluble template materials by using non-ionized polyelectrolytes in an organic phase (reverse-phase) instead of polyelectrolyte salts in an aqueous environment. By using the reverse-phase layer-by-layer (RP-LbL) technique, we have demonstrated the direct encapsulation of proteins, glucose, vitamin C, and inorganic salts in the solid state. Multilayer deposition was proven, layer thickness was determined by AFM, and the advantage of the method to prepare powders of encapsulated materials was demonstrated. The method is simple, robust, and applicable to a broad range of substances with potential applications in several industries.

  • 40.
    Bhatti, Adeel Liaquat
    et al.
    Univ Sindh, Pakistan.
    Aftab, Umair
    Mehran Univ Engn and Technol, Pakistan.
    Tahira, Aneela
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Abro, Muhammad Ishaq
    Mehran Univ Engn and Technol, Pakistan.
    Samoon, Muhammad Kashif
    Ctr Pure and Appl Geol Univ Sindh, Pakistan.
    Aghem, Muhammad Hassan
    Ctr Pure and Appl Geol Univ Sindh, Pakistan.
    Bhatti, Muhamad Ali
    Ctr Environm Sci, Pakistan.
    HussainIbupoto, Zafar
    Univ Sindh, Pakistan.
    Facile doping of nickel into Co3O4 nanostructures to make them efficient for catalyzing the oxygen evolution reaction2020Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, RSC ADVANCES, Vol. 10, nr 22, s. 12962-12969Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Designing a facile and low-cost methodology to fabricate earth-abundant catalysts is very much needed for a wide range of applications. Herein, a simple and straightforward approach was developed to tune the electronic properties of cobalt oxide nanostructures by doping them with nickel and then using them to catalyze the oxygen evolution reaction (OER) in an aqueous solution of 1.0 M KOH. The addition of a nickel impurity improved the conductivity of the cobalt oxide, and further increased its activity towards the OER. Analytical techniques such as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and powder X-ray diffraction (XRD) were used to investigate, respectively, the morphology, composition and crystalline structure of the materials used. The nickel-doped cobalt oxide material showed randomly oriented nanowires and a high density of nanoparticles, exhibited the cubic phase, and contained cobalt, nickel and oxygen as its main elements. The nickel-doped cobalt oxide also yielded a Tafel slope of 82 mV dec(-1) and required an overpotential of 300 mV to reach a current density of 10 mA cm(-2). As an OER catalyst, it was shown to be durable for 40 h. Electrochemical impedance spectroscopy (EIS) analysis showed a low charge-transfer resistance of 177.5 ohms for the nickel-doped cobalt oxide, which provided a further example of its excellent OER performance. These results taken together indicated that nickel doping of cobalt oxide can be accomplished via a facile approach and that the product of this doping can be used for energy and environmental applications.

    Fulltekst (pdf)
    fulltext
  • 41.
    Bhatti, Muhammad Ali
    et al.
    Univ Sindh Jamshoro, Pakistan.
    Shah, Aqeel Ahmed
    NED Univ Engn and Technol Karachi, Pakistan.
    Almani, Khalida Faryal
    Univ Sindh Jamshoro, Pakistan.
    Tahira, Aneela
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Chalangar, Seyed Ebrahim
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Chandio, Ali Dad
    NED Univ Engn and Technol Karachi, Pakistan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Ibupoto, Zafar Hussain
    Univ Sindh Jamshoro, Pakistan.
    Efficient photo catalysts based on silver doped ZnO nanorods for the photo degradation of methyl orange2019Inngår i: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 45, nr 17, s. 23289-23297Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, the doped ZnO nanorods with silver (Ag) as photosensitive material are prepared by the solvothermal method. The structural and optical characterization is carried out by the scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and UV-visible spectroscopy. The use of Ag as dopant did not alter the morphology of ZnO except sample 4 which has flower like morphology. The Ag, Zn and O are the main constituent of doped materials. The XRD revealed a hexagonal phase for ZnO and cubic phase for silver and confirmed the successful doping of Ag. The photocatalytic activity of Ag doped ZnO nanorods was investigated for the photo degradation of methyl orange. The photocatalytic measurements show that 88% degradation of methyl orange by the sample 4 within the 2 h of UV light treatment (365 nm) is significant advancement in the photocatalyst and provide the inexpensive and promising materials for the photochemical applications.

    Fulltekst tilgjengelig fra 2021-08-03 12:55
  • 42.
    Björk, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Synthesizing and Characterizing Mesoporous Silica SBA-15: A Hands On Laboratory Experiment for Undergraduates Using Various Instrumental Techniques2017Inngår i: Journal of Chemical Education, ISSN 0021-9584, E-ISSN 1938-1328, Vol. 94, nr 1, s. 91-94Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this laboratory experiment, students learn how to synthesize mesoporous silica of the SBA-15 type and explore how the different synthesis steps affect the final material. Mesoporous materials, especially SBA-15, are often used in the development of new methods for. drug delivery, catalysis, and separation because of the flexibility of tailoring these materials to optimize the performance in different applications. However, the synthesis of mesoporous materials is rarely introduced to undergraduate students. The material synthesis is a simple sol gel process, where small alterations in the synthesis steps can significantly change the material characteristics. The presented laboratory experiment aims to introduce undergraduate students to the synthesis of SBA-15 mesoporous silica with different pore sizes due to alterations in the hydrothermal treatment time and/ or temperature and to give students hands-on experience with important characterization tools, including physisorption, X-ray diffraction, FTIR spectroscopy, and thermogravimetric analysis, to understand the effect of hydrothermal treatment and surfactant removal. Additional synthesis parameters to study, such as surfactant removal, the silica precursor, and pore swelling agents, are also presented. The experiment has been used in teaching of both bachelors and masters students and can be adapted to various instrumental techniques, e.g., scanning electron microscopy for morphology studies, transition electron microscopy for pore structure characterization, etc.

    Fulltekst (pdf)
    fulltext
  • 43.
    Björk, Emma
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Univ Ulm, Germany.
    Mäkie, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Atakan, Aylin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Schell, Norbert
    Helmholtz Zentrum Geesthacht, Germany.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Formation of block-copolymer-templated mesoporous silica2018Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 521, s. 183-189Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In situ attenuated total reflectance Fourier transform infrared spectroscopy is used to monitor the chemical evolution of the mesoporous silica SBA-15 from hydrolysis of the silica precursor to final silica condensation after the particle formation. Two silica precursors, tetraethyl orthosilicate (TEOS) or sodium metasilicate (SMS) were used, and the effects of additive (heptane and NH4F) concentrations were studied. Five formation stages are identified when TEOS is used as the precursor. The fourth stage correlates with the appearance and evolution of diffraction peaks recorded using in situ small angle X-ray diffraction. Details of the formed silica matrix are observed, e.g. the ratio between six-fold cyclic silica rings and linear bonding increases with the NH4F concentration. The TEOS hydrolysis time is independent of the NH4F concentration for small amounts of heptane, but is affected by the size of the emulsion droplets when the heptane amount increases. Polymerization and condensation rates of both silica precursors are affected by the salt concentration. Materials synthesized using SMS form significantly faster compared to TEOS-materials due to the pre-hydrolysis of the precursor. The study provides detailed insights into how the composition of the synthesis solution affects the chemical evolution and micellar aggregation during formation of mesoporous silica. (C) 2018 Elsevier Inc. All rights reserved.

    Fulltekst (pdf)
    fulltext
  • 44.
    Blomqvist, A
    et al.
    Sandvik Tooling.
    Århammar, Cecilia
    Uppsala University.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Silvearv, Fredrik
    Uppsala University.
    Norgren, Susanne
    Sandvik Mining and Construction.
    Ahuja, R
    Uppsala University.
    Understanding the catalytic effects of H2S on CVD-growth of α-alumina: Thermodynamic gas-phase simulations and density functional theory2011Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 206, nr 7, s. 1771-1779Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The catalytic effect of H2S on the AlCl3/H2/CO2/HCl chemical vapor deposition (CVD) process has been investigatedon an atomistic scale. We apply a combined approach with thermodynamic modeling and densityfunctional theory and show that H2S acts as mediator for the oxygenation of the Al-surface which will inturn increase the growth rate of Al2O3. Furthermore we suggest surface terminations for the three investigatedsurfaces. The oxygen surface is found to be hydrogenated, in agreement with a number of previous works.The aluminum surfaces are Cl-terminated in the studied CVD-process. Furthermore, we find that the AlClOmolecule is a reactive transition state molecule which interacts strongly with the aluminum and oxygensurfaces.

  • 45. Bestill onlineKjøp publikasjonen >>
    Bouhafs, Chamseddine
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Structural and Electronic Properties of Graphene on 4H- and 3C-SiC2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Graphene is a one-atom-tick carbon layer arranged in a honeycomb lattice. Graphene was first experimentally demonstrated by Andre Geim and Konstantin Novoselov in 2004 using mechanical exfoliation of highly oriented pyrolytic graphite (exfoliated graphene flakes), for which they received the Nobel Prize in Physics in 2010. Exfoliated graphene flakes show outstanding electronic properties, e.g., very high free charge carrier mobility parameters and ballistic transport at room temperature. This makes graphene a suitable material for next generation radio-frequency and terahertz electronic devices. Such applications require fabrication methods of large-area graphene compatible with electronic industry. Graphene grown by sublimation on silicon carbide (SiC) offers a viable route towards production of large-area, electronic-grade material on semi-insulating substrate without the need of transfer. Despite the intense investigations in the field, uniform wafer-scale graphene with very high-quality that matches the properties of exfoliated graphene has not been achieved yet. The key point is to identify and control how the substrate affects graphene uniformity, thickness, layer stacking, structural and electronic properties. Of particular interest is to understand the effects of SiC surface polarity and polytype on graphene properties in order to achieve large-area material with tailored properties for electronic applications. The main objectives of this thesis are to address these issues by investigating the structural and electronic properties of epitaxial graphene grown on 4HSiC and 3C-SiC substrates with different surface polarities. The first part of the thesis includes a general description of the properties of graphene, bilayer graphene and graphite. Then, the properties of epitaxial graphene on SiC by sublimation are detailed. The experimental techniques used to characterize graphene are described. A summary of all papers and contribution to the field is presented at the end of Part I. Part II consists of seven papers.

    Delarbeid
    1. Structural properties and dielectric function of graphene grown by high-temperature sublimation on 4H-SiC(000-1)
    Åpne denne publikasjonen i ny fane eller vindu >>Structural properties and dielectric function of graphene grown by high-temperature sublimation on 4H-SiC(000-1)
    Vise andre…
    2015 (engelsk)Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, nr 8, s. 085701-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Understanding and controlling growth of graphene on the carbon face (C-face) of SiC presents a significant challenge. In this work, we study the structural, vibrational, and dielectric function properties of graphene grown on the C-face of 4H-SiC by high-temperature sublimation in an argon atmosphere. The effect of growth temperature on the graphene number of layers and crystallite size is investigated and discussed in relation to graphene coverage and thickness homogeneity. An amorphous carbon layer at the interface between SiC and the graphene is identified, and its evolution with growth temperature is established. Atomic force microscopy, micro-Raman scattering spectroscopy, spectroscopic ellipsometry, and high-resolution cross-sectional transmission electron microscopy are combined to determine and correlate thickness, stacking order, dielectric function, and interface properties of graphene. The role of surface defects and growth temperature on the graphene growth mechanism and stacking is discussed, and a conclusion about the critical factors to achieve decoupled graphene layers is drawn. (C) 2015 AIP Publishing LLC.

    sted, utgiver, år, opplag, sider
    American Institute of Physics (AIP), 2015
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-117253 (URN)10.1063/1.4908216 (DOI)000351132500070 ()
    Merknad

    Funding Agencies|Marie Curie actions [264613-NetFISiC]; Swedish Research Council (VR) [2011-4447, 2013-5580]; Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program [2011-03486]; Swedish foundation for strategic research (SSF) [FFL12-0181]; FP7 EU project Nano-Rf [FP7-ICT-2011-8]; French ANR under the Grafonics Project [ANR-10-NANO-0004]; European Union Seventh Framework Programme under Graphene Flagship [604391]; Knut and Alice Wallenbergs foundation

    Tilgjengelig fra: 2015-04-22 Laget: 2015-04-21 Sist oppdatert: 2017-12-04
    2. Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies
    Åpne denne publikasjonen i ny fane eller vindu >>Cavity-enhanced optical Hall effect in epitaxial graphene detected at terahertz frequencies
    Vise andre…
    2017 (engelsk)Inngår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 421, s. 357-360Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Cavity-enhanced optical Hall effect at terahertz (THz) frequencies is employed to determine the free charge carrier properties in epitaxial graphene (EG) with different number of layers grown by high-temperature sublimation on 4H-SiC(0001). We find that one monolayer (ML) EG possesses p-type conductivity with a free hole concentration in the low 1012 cmᅵᅵᅵ2 range and a free hole mobility parameter as high as 1550 cm2/Vs. We also find that 6 ML EG shows n-type doping behavior with a much lower free electron mobility parameter of 470 cm2/Vs and an order of magnitude higher free electron density in the low 1013 cmᅵᅵᅵ2 range. The observed differences are discussed. The cavity-enhanced THz optical Hall effect is demonstrated to be an excellent tool for contactless access to the type of free charge carriers and their properties in two-dimensional materials such as EG.

    sted, utgiver, år, opplag, sider
    Elsevier, 2017
    Emneord
    THz optical Hall effect, Epitaxial graphene, Free charge carrier properties
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-132407 (URN)10.1016/j.apsusc.2016.10.023 (DOI)000408756700015 ()
    Merknad

    Funding agencies: Swedish Research Council (VR) [2013-5580]; Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program [2011-03486, 2014-04712]; Swedish foundation for strategic research (SSF) [FFL12-0181, RIF14-055]

    Tilgjengelig fra: 2016-11-09 Laget: 2016-11-09 Sist oppdatert: 2019-03-05bibliografisk kontrollert
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    Structural and Electronic Properties of Graphene on 4H- and 3C-SiC
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  • 46.
    Brodin, Håkan
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial. Linköpings universitet, Tekniska högskolan. Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Eriksson, Robert
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Johansson, Sten
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Sjöström, Sören
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan. Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Fracture Mechanical Modelling of a Plasma Sprayed TBC System2009Inngår i: Advanced Ceramic Coatings and Interfaces IV / [ed] Dongming Zhu and Hua-Tay Lin, Westerville, OH, United States: American Ceramic Society Inc. , 2009, Vol. 30, nr 3, s. 113-124Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A thermal barrier coating (TBC) system subjected to thermal cycling will develop a microcrack partem near the interface between the metallic bond coat and the ceramic top coat. These small cracks link up and form internal TBC delaminations during repeated heating / cooling. After a longer time period, the internal delamination cracks will form a larger spallation damage, where the TBC is detached from the underlying material. Since cracks are initiated in multiple sites of the thermal barrier coating, the damage is initially considered to be governed by local stress conditions. The purpose of the present work is to compare experimental data with predictions of a physically based fatigue life model. The present study has been performed on plasma-sprayed TBCs where the interface geometry has been varied. In the present work, calculation of fatigue life is done for a number of cases under thermal fatigue loading. Different interface geometries are compared in order to understand the influence of variations in the TC/BC interface roughness on oxidation behaviour and thermal fatigue life. Thermal fatigue tests indicate that an increased surface roughness is beneficial from a fatigue life point of view.

  • 47.
    Brooke, Robert
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Franco Gonzalez, Felipe
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Wijeratne, Kosala
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Pavlopoulou, Eleni
    Univ Bordeaux, France.
    Galliani, Daniela
    Univ Milano Bicocca, Italy.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Valiollahi Bisheh, Roudabeh
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Zozoulenko, Igor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Vapor phase synthesized poly(3,4-ethylenedioxy-thiophene)-trifluoromethanesulfonate as a transparent conductor material2018Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, nr 43, s. 21304-21312Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Inorganic transparent conductive oxides have dominated the market as transparent electrodes due to their high conductivity and transparency. Here, we report the fabrication and optimization of the synthesis of poly(3,4-ethylenedioxythiophene) trifluoromethanesulfonate via vapor phase polymerization for the potential replacement of such inorganic materials. The parameters and conditions of the polymerization were investigated and an electrical conductivity of 3800 S cm(-1) and 4500 S cm(-1) after acid treatment were obtained while maintaining an absorbance similar to that of commercial indium tin oxide. This increase in electrical conductivity was rationalized experimentally and theoretically to an increase in the oxidation level and a higher order of crystallinity which does not disrupt the pi-pi stacking of PEDOT chains.

    Fulltekst (pdf)
    fulltext
  • 48.
    Byeon, Ayeong
    et al.
    Drexel University, PA 19104 USA; Drexel University, PA 19104 USA; Korea Adv Institute Science and Technology, South Korea.
    Zhao, Meng-Qiang
    Drexel University, PA 19104 USA; Drexel University, PA 19104 USA.
    Ren, Chang E.
    Drexel University, PA 19104 USA; Drexel University, PA 19104 USA.
    Halim, Joseph
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Drexel University, PA 19104 USA; Drexel University, PA 19104 USA.
    Kota, Sankalp
    Drexel University, PA 19104 USA.
    Urbankowski, Patrick
    Drexel University, PA 19104 USA.
    Anasori, Babak
    Drexel University, PA 19104 USA.
    Barsoum, Michel W.
    Drexel University, PA 19104 USA.
    Gogotsi, Yury
    Drexel University, PA 19104 USA.
    Two-Dimensional Titanium Carbide MXene As a Cathode Material for Hybrid Magnesium/Lithium-Ion Batteries2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 5, s. 4296-4300Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As an alternative to pure lithium-ion, Lit, systems, a hybrid magnesium, Mg2+, and Li+ battery can potentially combine the high capacity, high voltage, and fast Li+ intercalation of Li-ion battery cathodes and the high capacity, low cost, and dendrite-free Mg metal anodes. Herein, we report on the use of two-dimensional titanium carbide, Ti3C2Tx (MXene), as a cathode in hybrid Mg2+/Li+ batteries, coupled with a Mg metal anode. Free-standing and flexible Ti3C2Tx/carbon nanotube composite "paper" delivered-,100 mAh at 0.1 C and similar to 50 mAh g(-1) at 10 C. At 1 C the capacity was maintained for amp;gt;500 cycles at 80 mAh g(-1). The Mo2CTx MXene also demonstrated good performance as a cathode material in this hybrid battery. Considering the variety of available MXenes, this work opens the door for exploring a new large family of 2D materials with high electrical conductivity and large intercalation capacity as cathodes for hybrid Mg2+/Li+ batteries.

  • 49.
    Bykov, M.
    et al.
    Univ Bayreuth, Germany.
    Bykova, E.
    Univ Bayreuth, Germany; DESY, Germany.
    Aprilis, G.
    Univ Bayreuth, Germany.
    Glazyrin, K.
    DESY, Germany.
    Koemets, E.
    Univ Bayreuth, Germany.
    Chuvashova, I
    Univ Bayreuth, Germany; Univ Bayreuth, Germany.
    Kupenko, I
    Univ Munster, Germany.
    McCammon, C.
    Univ Bayreuth, Germany.
    Mezouar, M.
    European Synchrotron Radiat Facil, France.
    Prakapenka, V
    Univ Chicago, IL 60437 USA.
    Liermann, H-P
    DESY, Germany.
    Tasnadi, Ferenc
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Natl Univ Sci and Technol MISIS, Russia.
    Ponomareva, A. V
    Natl Univ Sci and Technol MISIS, Russia.
    Abrikosov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Dubrovinskaia, N.
    Univ Bayreuth, Germany.
    Dubrovinsky, L.
    Univ Bayreuth, Germany.
    Fe-N system at high pressure reveals a compound featuring polymeric nitrogen chains2018Inngår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, artikkel-id 2756Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Poly-nitrogen compounds have been considered as potential high energy density materials for a long time due to the large number of energetic N-N or N=N bonds. In most cases high nitrogen content and stability at ambient conditions are mutually exclusive, thereby making the synthesis of such materials challenging. One way to stabilize such compounds is the application of high pressure. Here, through a direct reaction between Fe and N-2 in a laser-heated diamond anvil cell, we synthesize three ironnitrogen compounds Fe3N2, FeN2 and FeN4. Their crystal structures are revealed by single-crystal synchrotron X-ray diffraction. Fe3N2, synthesized at 50 GPa, is isostructural to chromium carbide Cr3C2. FeN2 has a marcasite structure type and features covalently bonded dinitrogen units in its crystal structure. FeN4, synthesized at 106 GPa, features polymeric nitrogen chains of [N-4(2-)](n) units. Based on results of structural studies and theoretical analysis, [N-4(2-)](n) units in this compound reveal catena-poly[tetraz-1-ene-1,4-diyl] anions.

    Fulltekst (pdf)
    fulltext
  • 50.
    Bykova, E.
    et al.
    DESY, Germany; Univ Bayreuth, Germany.
    Bykov, M.
    Univ Bayreuth, Germany; Natl Univ Sci and Technol MISIS, Russia.
    Cernok, A.
    Univ Bayreuth, Germany; Open Univ, England.
    Tidholm, Johan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Simak, Sergey
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Hellman, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. CALTECH, CA 91125 USA.
    Belov, M. P.
    Natl Univ Sci and Technol MISIS, Russia.
    Abrikosov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Liermann, H. -P.
    DESY, Germany.
    Hanfland, M.
    European Synchrotron Radiat Facil, France.
    Prakapenka, V. B.
    Univ Chicago, IL 60637 USA.
    Prescher, C.
    Univ Chicago, IL 60637 USA; Univ Cologne, Germany.
    Dubrovinskaia, N.
    Univ Bayreuth, Germany.
    Dubrovinsky, L.
    Univ Bayreuth, Germany.
    Metastable silica high pressure polymorphs as structural proxies of deep Earth silicate melts2018Inngår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, artikkel-id 4789Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modelling of processes involving deep Earth liquids requires information on their structures and compression mechanisms. However, knowledge of the local structures of silicates and silica (SiO2) melts at deep mantle conditions and of their densification mechanisms is still limited. Here we report the synthesis and characterization of metastable high-pressure silica phases, coesite-IV and coesite-V, using in situ single-crystal X-ray diffraction and ab initio simulations. Their crystal structures are drastically different from any previously considered models, but explain well features of pair-distribution functions of highly densified silica glass and molten basalt at high pressure. Built of four, five-, and six-coordinated silicon, coesite-IV and coesite-V contain SiO6 octahedra, which, at odds with 3rd Paulings rule, are connected through common faces. Our results suggest that possible silicate liquids in Earths lower mantle may have complex structures making them more c