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  • 1.
    Abdollahi Sani, Negar
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Robertsson, Mats
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Cooper, Philip
    De La Rue Plc, Overton, Hampshire, UK .
    Wang, Xin
    Acreo AB, Norrköping, Sweden.
    Svensson, Magnus
    Acreo AB, Norrköping, Sweden.
    Andersson Ersman, Peter
    Acreo AB, Norrköping, Sweden.
    Norberg, Petronella
    Acreo AB, Norrköping, Sweden.
    Nilsson, Marie
    Acreo AB, Norrköping, Sweden.
    Nilsson, David
    Acreo AB, Norrköping, Sweden.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Hesselbom, Hjalmar
    Hesselbom Innovation and Development HB, Huddinge, Sweden .
    Akesso, Laurent
    De La Rue Plc, Overton, Hampshire, UK .
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Engquist, Isak
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Acreo AB, Norrköping, Sweden.
    Gustafsson, Goran
    Acreo AB, Norrköping, Sweden.
    All-printed diode operating at 1.6 GHz2014In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 111, no 33, p. 11943-11948Article in journal (Refereed)
    Abstract [en]

    Printed electronics are considered for wireless electronic tags and sensors within the future Internet-of-things (IoT) concept. As a consequence of the low charge carrier mobility of present printable organic and inorganic semiconductors, the operational frequency of printed rectifiers is not high enough to enable direct communication and powering between mobile phones and printed e-tags. Here, we report an all-printed diode operating up to 1.6 GHz. The device, based on two stacked layers of Si and NbSi2 particles, is manufactured on a flexible substrate at low temperature and in ambient atmosphere. The high charge carrier mobility of the Si microparticles allows device operation to occur in the charge injection-limited regime. The asymmetry of the oxide layers in the resulting device stack leads to rectification of tunneling current. Printed diodes were combined with antennas and electrochromic displays to form an all-printed e-tag. The harvested signal from a Global System for Mobile Communications mobile phone was used to update the display. Our findings demonstrate a new communication pathway for printed electronics within IoT applications.

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  • 2.
    Adam, Rania Elhadi
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    Nur, Omer
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    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 light2020In: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 99, article id 106053Article in journal (Refereed)
    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.

  • 3.
    Adam, Rania Elhadi
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Chalangar, Ebrahim
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering. School of Information Technology, Halmstad University, Halmstad, Sweden.
    Pirhashemi, Mahsa
    Department of Chemistry, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Pettersson, Håkan
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering. School of Information Technology, Halmstad University, Halmstad, Sweden; Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Willander, Magnus
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities2019In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 52, p. 30585-30598Article in journal (Refereed)
    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.

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  • 4.
    Ali Abbasi, Mazhar
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain Ibupoto, Zafar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    The determination of valence band offset and the current transport properties of the p-NiO/n-ZnO heterojunction2013Manuscript (preprint) (Other academic)
    Abstract [en]

    The electron transport in the electronic devices has significant influence on the device performance, thus current transport properties determination is highly demanded for a particular device. Herein, we report the facile hydrothermal growth method based fabrication of p-NiO/n-ZnO heterojunction. The material characterization was performed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy and X-ray photo electron spectroscopy. These techniques provided the good crystal quality, pure phase of p-NiO and n-ZnO nanostructures respectively. The measured valance band offset of composite nanostructure is 2.25 eV and conduction band offset was found to be 2.58 eV. The current transport properties of the fabricated p-n junction are governed by three different I-V regions. The impedance spectroscopy was used for the determination of the role of grain boundaries at the interface.

  • 5.
    Alnoor, Hatim
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Chey, Chan Oeurn
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Effect of precursor solutions stirring on deep level defects concentration and spatial distribution in low temperature aqueous chemical synthesis of zinc oxide nanorods2015In: AIP Advances, E-ISSN 2158-3226, Vol. 5, no 8, article id 087180Article in journal (Refereed)
    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.

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  • 6.
    Alnoor, Hatim
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Iandolo, Donata
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    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 diodes2016In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, no 16, p. 165702-Article in journal (Refereed)
    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.

  • 7.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Sun, Zhengyi
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Energy Level Bending in Ultrathin Polymer Layers Obtained through Langmuir-Shafer Deposition2016In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 7, p. 1077-1084Article in journal (Refereed)
    Abstract [en]

    The semiconductor-electrode interface impacts the function and the performance of (opto) electronic devices. For printed organic electronics the electrode surface is not atomically clean leading to weakly interacting interfaces. As a result, solution-processed organic ultrathin films on electrodes typically form islands due to dewetting. It has therefore been utterly difficult to achieve homogenous ultrathin conjugated polymer films. This has made the investigation of the correct energetics of the conjugated polymer-electrode interface impossible. Also, this has hampered the development of devices including ultrathin conjugated polymer layers. Here, LangmuirShafer-manufactured homogenous mono-and multilayers of semiconducting polymers on metal electrodes are reported and the energy level bending using photoelectron spectroscopy is tracked. The amorphous films display an abrupt energy level bending that does not extend beyond the first monolayer. These findings provide new insights of the energetics of the polymer-electrode interface and opens up for new high-performing devices based on ultrathin semiconducting polymers.

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  • 8.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Sun, Zhengyi
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    The energetics of the semiconducting polymer-electrode interface for solution-processed electronicsManuscript (preprint) (Other academic)
    Abstract [en]

    The semiconductor-electrode interface impacts the function and the performance of (opto-)electronic devices. For printed organic electronics the electrode surface is not atomically clean leading to weakly interacting interfaces. As a result, solution-processed organic ultra-thin films on electrodes typically form islands due to de-wetting. It has therefore been utterly difficult to achieve homogenous ultrathin conjugated polymer films. This has made the investigation of the correct energetics of the conjugated polymer-electrode interface impossible. Also, this has hampered the development of devices including ultra-thin conjugated polymer layers. Here, we report Langmuir-Shäfer-manufactured homogenous mono- and multilayers of semiconducting polymers on metal electrodes and track the energy level bending using photoelectron spectroscopy. The amorphous films display an abrupt energy level bending that does not extend beyond the first monolayer. Our findings provide new insights of the energetics of the polymer-electrode interface and opens up for new high-performing devices based on ultra-thin semiconducting polymers.

  • 9.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Oxygen- and Water-Based Degradation in [6,6]-Phenyl-C-61-Butyric Acid Methyl Ester (PCBM) Films2014In: Advanced Energy Materials, ISSN 1614-6832, E-ISSN 1614-6840, Vol. 4, no 6Article in journal (Refereed)
    Abstract [en]

    Effects of in situ oxygen/water exposure on the energetics of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) films are presented. For oxygen exposure, the work function is downshifted by ≈0.15 eV compared to the ideal integer charge transfer (ICT) curve for pristine PCBM, which is incompatible with significant introduction of electron trap states or p-doping. Water induces the highest occupied molecular orbital (HOMO) structure to undergo strong, irreversible modifications accompanied by a chemical interaction with PCBM.

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  • 10.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Energetics at Doped Conjugated Polymer/Electrode Interfaces2015In: ADVANCED MATERIALS INTERFACES, ISSN 2196-7350, Vol. 2, no 2Article in journal (Refereed)
    Abstract [en]

    n/a

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  • 11.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering. Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, P.R. China.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Yanqing, Li
    Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, P.R. China.
    Jianxin, Tang
    Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, P.R. China.
    Chungang, Duan
    Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, P.R. China.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Intermixing Effect on Electronic Structures of TQ1:PC71BM Bulk Heterojunction in Organic Photovoltaics2017In: Solar RRL, E-ISSN 2367-198X, Vol. 1, no 10, article id 1700142Article in journal (Refereed)
    Abstract [en]

    The interface energetics and intermixing effects of the donor/acceptor bulk heterojunction (BHJ) blends of poly[2,3‐bis‐(3‐octyloxyphenyl) quinoxaline‐5, 8‐dilyl‐alt‐thiophene‐2, 5‐diyl]: [6,6]‐phenyl C71butyric acid methyl ester (TQ1:PC71BM) have been investigated using ultraviolet photoemission spectroscopy (UPS) in combination with the integer charge transfer model. The TQ1:PC71BM represents the useful model system for BHJ organic photovoltaics featuring effective charge generation and transport. It finds out that the positive integer charge state of TQ1 are equal in energy to the negative integer charge state of PC71BM, leading to a negligible potential step at TQ1:PC71BM interface and thus the vacuum level alignment. It is observed that the TQ1 accumulates on the top of TQ1:PC71BM BHJ and UPS spectra as function of various blend ratios suggest that the TQ1 mixes finely with PC71BM with the little work function modification in a wide range. In addition, no significant influence of the long‐range Coulomb interactions or the intermolecular hybridization on the occupied electronic structures is present for the well‐intermixed TQ1:PC71BM BHJs. These findings provide deep insights into the properties of BHJ blends and are beneficial for the performance optimization in organic photovoltaics.

  • 12.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Wang, Ergang
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, Sweden.
    Fang, Junfeng
    Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo, PR China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, P. R. China.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Regular Energetics at Conjugated Electrolyte/Electrode Modifier for Organic Electronics and Their Implications of Design Rules2015In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 2, no 12, p. 1-6, article id 1500204Article in journal (Refereed)
    Abstract [en]

    Regular energetics at a conjugated electrolyte/electrode modifier are found and controlled by equilibration of the Fermi level and an additional interface double dipole step induced by ionic functionality. Based on the results, design rules for conjugated electrolyte/electrode modifiers to achieve the smallest charge injection/exaction barrier and break through the current thickness limitation are proposed.

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  • 13.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Xia, Yuxin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Kauffmann, Louis-Dominique
    GenesInk, France.
    Margeat, Olivier
    Aix Marseille University, France.
    Ackermann, Jorg
    Aix Marseille University, France.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Effects of ultraviolet soaking on surface electronic structures of solution processed ZnO nanoparticle films in polymer solar cells2014In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 2, no 41, p. 17676-17682Article in journal (Refereed)
    Abstract [en]

    We systematically show the effect of UV-light soaking on surface electronic structures and chemical states of solution processed ZnO nanoparticle (ZnONP) films in UHV, dry air and UV-ozone. UV exposure in UHV induces a slight decrease in work function and surface-desorption of chemisorbed oxygen, whereas UV exposure in the presence of oxygen causes an increase in work function due to oxygen atom vacancy filling in the ZnO matrix. We demonstrate that UV-light soaking in combination with vacuum or oxygen can tune the work function of the ZnONP films over a range exceeding 1 eV. Based on photovoltaic performance and diode measurements, we conclude that the oxygen atom vacancy filling occurs mainly at the surface of the ZnONP films and that the films consequently retain their n-type behavior despite a significant increase in the measured work function.

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  • 14.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Sandberg, Oskar
    Abo Akad University, Finland.
    Dagnelund, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Sanden, Simon
    Abo Akad University, Finland.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Aarnio, Harri
    Abo Akad University, Finland.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Chen, Weimin
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Osterbacka, Ronald
    Abo Akad University, Finland.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Trap-Assisted Recombination via Integer Charge Transfer States in Organic Bulk Heterojunction Photovoltaics2014In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 24, no 40, p. 6309-6316Article in journal (Refereed)
    Abstract [en]

    Organic photovoltaics are under intense development and significant focus has been placed on tuning the donor ionization potential and acceptor electron affinity to optimize open circuit voltage. Here, it is shown that for a series of regioregular-poly(3-hexylthiophene): fullerene bulk heterojunction (BHJ) organic photovoltaic devices with pinned electrodes, integer charge transfer states present in the dark and created as a consequence of Fermi level equilibrium at BHJ have a profound effect on open circuit voltage. The integer charge transfer state formation causes vacuum level misalignment that yields a roughly constant effective donor ionization potential to acceptor electron affinity energy difference at the donor-acceptor interface, even though there is a large variation in electron affinity for the fullerene series. The large variation in open circuit voltage for the corresponding device series instead is found to be a consequence of trap-assisted recombination via integer charge transfer states. Based on the results, novel design rules for optimizing open circuit voltage and performance of organic bulk heterojunction solar cells are proposed.

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  • 15.
    Boerrnert, Felix
    et al.
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Boerrnert, Carina
    Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany.
    Gorantla, Sandeep
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Bachmatiuk, Alicja
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Joswig, Jan-Ole
    Technische Universität Dresden, Dresden, Germany.
    Wagner, Frank P
    Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany.
    Schaeffel, Franziska
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Warner, Jamie H
    University of Oxford, Oxford, United Kingdom.
    Schoenfelder, Ronny
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Rellinghaus, Bernd
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Gemming, Thomas
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Thomas, Juergen
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Knupfer, Martin
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Buechner, Bernd
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany.
    Ruemmeli, Mark H
    Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e. V., Dresden, Germany and Technische Universität Dresden, Dresden, Germany.
    Single-wall-carbon-nanotube/single-carbon-chain molecular junctions2010In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 81, no 8, p. 085439-1-085439-5Article in journal (Refereed)
    Abstract [en]

    Stable junctions between a single carbon chain and two single-wall carbon nanotubes were produced via coalescence of functionalized fullerenes filled into a single-wall carbon nanotube and directly imaged by in situ transmission electron microscopy. First principles quantum chemical calculations support the observed stability of such molecular junctions. They also show that short carbon chains bound to other carbon structures are cumulenes and stable semiconductors due to Peierls-like distortion. Junctions like this can be regarded as archetypical building blocks for all-carbon molecular electronics.

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  • 16.
    Braun, Slawomir
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Salaneck, William R
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Fermi level equilibrium at donor-acceptor interfaces in multi-layered thin film stack of TTF and TCNQ2010In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 11, no 2, p. 212-217Article in journal (Refereed)
    Abstract [en]

    Organic hetero-junctions in multi-layered thin film stacks comprising alternate layers of the molecular donor-tetrathiafulvalene (TTF) and the acceptor - tetracyanoquinodimethane (TCNQ), have been studied by ultraviolet photoelectron spectroscopy ( UPS). We show that the energy level alignment at the organic-organic interfaces in the stacks depends only upon the relative energy structure of the donor and acceptor molecules, in particular, the molecular integer charge transfer (ICT) states. The observed interfacial dipoles, across the multi-layered organic stacks, correspond to the difference in energy between the positive and the negative charge transfer states of the molecules constituting the interface. Consequently, Fermi level across the multi-layer system is pinned to those states, since the energetic conditions for the charge transfer across the interface are fulfilled. Hence the energy level alignment at donor - acceptor interfaces studied can be rationalized on the basis of integer charge transfer model (ICT-model). Moreover, we present the photoelectron spectra where 0.85 eV shift of the highest occupied molecular orbital (HOMO) of TTF during formation of TCNQ over-layer is directly observed. These studies contribute to the understanding of the nature of the offset between the frontier electronic levels of the donor and acceptor components which is of high importance in the engineering of efficient organic solar cells.

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  • 17.
    Briones-Leon, Antonio
    et al.
    University of Vienna, Austria.
    Ayala, Paola
    University of Vienna, Austria.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Yanagi, Kazuhiro
    Tokyo Metropolitan University, Japan.
    Weschke, Eugen
    Helmholtz Zentrum Berlin Mat and Energie, Germany.
    Eisterer, Michael
    Vienna University of Technology, Austria.
    Jiang, Hua
    Aalto University, Finland.
    Kataura, Hiromichi
    Nat Institute Adv Ind Science and Technology AIST, Japan.
    Pichler, Thomas
    University of Vienna, Austria.
    Shiozawa, Hidetsugu
    University of Vienna, Austria.
    Orbital and spin magnetic moments of transforming one-dimensional iron inside metallic and semiconducting carbon nanotubes2013In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 87, no 19Article in journal (Refereed)
    Abstract [en]

    The orbital and spin magnetic properties of iron inside metallic and semiconducting carbon nanotubes are studied by means of local x-ray magnetic circular dichroism (XMCD) and bulk superconducting quantum interference device (SQUID). The iron-nanotube hybrids are initially ferrocene filled single-walled carbon nanotubes (SWCNT) of different metallicities. We show that the ferrocene's molecular orbitals interact differently with the SWCNT of different metallicities with no significant XMCD response. At elevated temperatures the ferrocene molecules react with each other to form cementite nanoclusters. The XMCD at various magnetic fields reveal that the orbital and/or spin magnetic moments of the encapsulated iron are altered drastically as the transformation to the 1D clusters takes place. The orbital and spin magnetic moments are both found to be larger in filled semiconducting nanotubes than in the metallic sample. This could mean that the magnetic polarization of the encapsulated material depends on the metallicity of the tubes. From a comparison between the iron 3d magnetic moments and the bulk magnetism measured by SQUID, we conclude that the delocalized magnetisms dominate the magnetic properties of these 1D hybrid nanostructures.

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  • 18.
    Briones-Leon, Antonio
    et al.
    University of Vienna, Austria .
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Ayala, Paola
    University of Vienna, Austria .
    Kataura, Hiromichi
    National Institute Adv Ind Science and Technology, Japan .
    Yanagi, Kazuhiro
    Tokyo Metropolitan University, Japan .
    Weschke, Eugen
    Helmholtz Zentrum Berlin Fr Mat and Energie, Germany .
    Pichler, Thomas
    University of Vienna, Austria .
    Shiozawa, Hidetsugu
    University of Vienna, Austria .
    Orbital and spin magnetic moments of ferrocene encapsulated in metallicity sorted single-walled carbon nanotubes2012In: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 249, no 12, p. 2424-2427Article in journal (Refereed)
    Abstract [en]

    The nature of the electronic and local magnetic properties of ferrocene (FeCp2) filled single-walled carbon nanotubes (SWCNT) has been investigated by X-ray absorption spectroscopy (XAS) and magnetic circular dichroism (XMCD). Metallic, semiconducting, and unsorted ferrocene-filled tubes have been studied in different conditions of temperature and magnetic field. XMCD signal becomes evident with the application of a magnetic field at low temperature. We find that the molecular states of ferrocene interact with SWCNT of different metallicities. A paramagnetic behavior of encapsulated ferrocene is observed from the magnetic field dependent XMCD measurements which is consistent with theoretical predictions.

  • 19.
    Carlegrim, Elin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Zhan, Yiqiang
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Li, Fenghong
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Characterization of the Ni/V(TCNE)x interface for hybrid spintronics applications2010In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 11, no 6, p. 1020-1024Article in journal (Refereed)
    Abstract [en]

    Vanadium tetracyanoethylene, V(TCNE)x, is an organic-based magnet with properties suitable for spintronics applications, e.g. spin valves. In this paper we propose a new hybrid organic spin valve design where V(TCNE)x is used as a spin-transporting and spin-filtering layer sandwiched between two ferromagnetic (FM) metal contacts, i.e. FM/V(TCNE)x/FM. As the spin injection and detection of such a device occurs at the interfaces the quality of those are of crucial importance. Therefore, the Ni/V(TCNE)x interface has been investigated by X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption spectroscopy (NEXAFS) as well as compared with XPS results from a model system, Ni/TCNE. Ni chemically interact with both the vinyl and cyano groups but there is no evidence for significant diffusion of Ni into the V(TCNE)x film. As the chemical interaction affects the spin injection and detection negatively by modifying the lowest unoccupied molecular orbital (LUMO) and destroying the magnetic ordering network at the surface, these results indicate that there is need for a buffer layer between V(TCNE)x and Ni, and in extension most likely between V(TCNE)x and any FM contact.

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  • 20.
    Chen, Jing-De
    et al.
    Soochow Univ, Peoples R China.
    Li, Ling
    Soochow Univ, Peoples R China.
    Qin, Chao-Chao
    Henan Normal Univ, Peoples R China.
    Ren, Hao
    Soochow Univ, Peoples R China.
    Li, Yan-Qing
    East China Normal Univ, Peoples R China.
    Ou, Qing-Dong
    Monash Univ, Australia.
    Guo, Jia-Jia
    Henan Normal Univ, Peoples R China.
    Zou, Shi-Jie
    Soochow Univ, Peoples R China.
    Xie, Feng-Ming
    Soochow Univ, Peoples R China.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tang, Jian-Xin
    Soochow Univ, Peoples R China; Macau Univ Sci & Technol, Peoples R China.
    Hot-electron emission-driven energy recycling in transparent plasmonic electrode for organic solar cells2022In: InfoMat, ISSN 2567-3165, Vol. 4, no 3, article id e12285Article in journal (Refereed)
    Abstract [en]

    Plasmonic metal electrodes with subwavelength nanostructures are promising for enhancing light harvesting in photovoltaics. However, the nonradiative damping of surface plasmon polaritons (SPPs) during coupling with sunlight results in the conversion of the excited hot-electrons to heat, which limits the absorption of light and generation of photocurrent. Herein, an energy recycling strategy driven by hot-electron emission for recycling the SPP energy trapped in the plasmonic electrodes is proposed. A transparent silver-based plasmonic metal electrode (A-PME) with a periodic hexagonal nanopore array is constructed, which is combined with a luminescent organic emitter for radiative recombination of the injected hot-electrons. Owing to the suppressed SPP energy loss via broadband hot-electron emission, the A-PME achieves an optimized optical transmission with an average transmittance of over 80% from 380 to 1200 nm. Moreover, the indium-tin-oxide-free organic solar cells yield an enhanced light harvesting with a power conversion efficiency of 16.1%.

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  • 21.
    Chen, Shangzhi
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Petsagkourakis, Ioannis
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Spampinato, Nicoletta
    Univ. Bordeaux, CNRS, Bordeaux INP, LCPO, Pessac, France.
    Kuang, Chaoyang
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Brooke, Robert
    RISE Research Institutes of Sweden, Bio- and Organic Electronics, Norrköping, Sweden.
    Kang, Evan S. H.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Pavlopoulou, Eleni
    Univ. Bordeaux, CNRS, Bordeaux INP, LCPO, Pessac, France.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Unraveling vertical inhomogeneity in vapour phase polymerized PEDOT:Tos films2020In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 8, p. 18726-18734Article in journal (Refereed)
    Abstract [en]

    The conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) forms a promising alternative to conventional inorganic conductors, where deposition of thin films via vapour phase polymerization (VPP) has gained particular interest owing to high electrical conductivity within the plane of the film. The conductivity perpendicular to the film is typically much lower, which may be related not only to preferential alignment of PEDOT crystallites but also to vertical stratification across the film. In this study, we reveal non-linear vertical microstructural variations across VPP PEDOT:Tos thin films, as well as significant differences in doping level between the top and bottom surfaces. The results are consistent with a VPP mechanism based on diffusion-limited transport of polymerization precursors. Conducting polymer films with vertical inhomogeneity may find applications in gradient-index optics, functionally graded thermoelectrics, and optoelectronic devices requiring gradient doping.

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  • 22.
    Chen, Yongzhen
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Understanding Interface Dipoles at an Electron Transport Material/Electrode Modifier for Organic Electronics2021In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 13, no 39, p. 47218-47225Article in journal (Refereed)
    Abstract [en]

    Interface dipoles formed at an electrolyte/electrode interface have been widely studied and interpreted using the "double dipole step" model, where the dipole vector is determined by the size and/or range of motion of the charged ions. Some electron transport materials (ETMs) with lone pairs of electrons on heteroatoms exhibit a similar interfacial behavior. However, the origin of the dipoles in such materials has not yet been explored in great depth. Herein, we systematically investigate the influence of the lone pair of electrons on the interface dipole through three pyridine derivatives B2-B4PyMPM. Experiments show that different positions of nitrogen atoms in the three materials give rise to different hydrogen bonds and molecular orientations, thereby affecting the areal density and direction of the lone pair of electrons. The interface dipoles of the three materials predicted by the "double dipole step" model are in good agreement with the ultraviolet photoelectron spectroscopy results both in spin-coated and vacuum-deposited films. These findings help to better understand the ETMs/electrode interfacial behaviors and provide new guidelines for the molecular design of the interlayer.

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  • 23.
    Chen, Zhan
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering. Jinan Univ, Peoples R China.
    Liu, Xiaoke
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Wang, Heyong
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hou, Lintao
    Jinan Univ, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Photoluminescence Enhancement for Efficient Mixed-Halide Blue Perovskite Light-Emitting Diodes2023In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 11, no 6, article id 2202528Article in journal (Refereed)
    Abstract [en]

    The development of highly efficient blue perovskite light-emitting diodes (PeLEDs) remains a big challenge, requiring more fundamental investigations. In this work, significant photoluminescence enhancement in mixed halide blue perovskite films is demonstrated by using a molecule, benzylphosphonic acid, which eventually doubles the external quantum efficiency to 6.3% in sky-blue PeLEDs. The photoluminescence enhancement is achieved by forming an oxide-bonded perovskite surface at grain boundaries and suppressing electron-phonon interaction, which enhances the radiative recombination rate and reduces the nonradiative recombination rate, respectively. Moreover, severe thermal quenching is observed in the blue perovskite films, which can be explained by a two-step mechanism involving exciton dissociation and electron-phonon interaction. The results suggest that enhancing the radiative recombination rate and reducing the electron-phonon interaction-induced nonradiative recombination rate are crucial for achieving blue perovskite films with strong emission at or above room temperature.

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  • 24.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    ZnO nanorods based piezoresistive sensor synthesized by rapid mixing hydrothermal methodManuscript (preprint) (Other academic)
    Abstract [en]

    We have successfully synthesized well-aligned, shape controlled and uniform size distribution of ZnO nanorods by using a rapid mixing hydrothermal method. The scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations showed that the ZnO nanorods grow along the c-axis with hexagonal wurtzite ZnO structure. The room temperature cathodoluminescence (CL) investigation revealed that the ZnO nanorods have optical emissions in both the UV and visible ranges and the crystal quality of the ZnO nanorods can be improved by increasing the growth duration. The well-aligned and uniform ZnO nanorods were used to fabricate efficient piezoresistive sensor. The piezoresistive sensor has demonstrated a pressure sensitivity of 0.033 KPa-1 with a fast response and recovery times within 0.088 and 0.29 s, respectively. The piezoresistive sensor has potential applications in industrial, civil and transportation fields. Furthermore, the fabricated sensor can be utilized as a very useful human-friendly interactive electronic device for load sensing.

  • 25.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Fast piezoresistive sensor and UV photodetector based on Mn-doped ZnO nanorods2015In: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 9, no 1, p. 87-91Article in journal (Refereed)
    Abstract [en]

    A low cost hydrothermal synthesis method to synthesize Mn-doped ZnO nanorods (NRs) with controllable morphology and structure has been developed. Ammonia is used to tailor the ammonium hydroxide concentration, which provides a source of OH– for hydrolysis and precipitation during the growth instead of HMT. The morphological, chemical composition, structural, and electronic structure studies of the Mn-doped ZnO NRs show that the Mn-doped ZnO NRs have a hexagonal wurtzite ZnO structure along the c-axis and the Mn ions replace the Zn sites in the ZnO NRs matrix without any secondary phase of metallic manganese element and manganese oxides observed. The fabricated PEDOT:PSS/Zn0.85Mn0.15O Schottky diode based piezoresistive sensor and UV photodetector shows that the piezoresistive sensor has pressure sensitivity of 0.00617 kPa–1 for the pressure range from 1 kPa to 20 kP and 0.000180 kPa–1for the pressure range from 20 kPa to 320 kPa with relatively fast response time of 0.03 s and the UV photodetector has both relatively high responsivity and fast response time of 0.065 A/W and 2.75 s, respectively. The fabricated Schottky diode can be utilized as a very useful human-friendly interactive electronic device for mass/force sensor or UV photodetector in everyday living life. This developed device is very promising for small-size, low-cost and easy-to-customize application-specific requirements. (© 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

  • 26.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Masood, Ansar
    Department of Materials Science, Royal Institute of Technology, Stockholm, Sweden.
    Riazanova, A.
    Department of Materials Science, Royal Institute of Technology, Stockholm, Sweden.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Rao, K. V.
    Department of Materials Science, Royal Institute of Technology, Stockholm, Sweden.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Synthesis of Fe-Doped ZnO Nanorods by Rapid Mixing Hydrothermal Method and Its Application for High Performance UV Photodetector2014In: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, Vol. 2014, no 524530, p. 1-9Article in journal (Refereed)
    Abstract [en]

    We have successfully synthesized Fe-doped ZnO nanorods by a new and simple method in which the adopted approach is by using ammonia as a continuous source of OH for hydrolysis instead of hexamethylenetetramine (HMT). The energy dispersive X-ray (EDX) spectra revealed that the Fe peaks were presented in the grown Fe-doped ZnO nanorods samples and the X-ray photoelectron spectroscopy (XPS) results suggested that Fe3+ is incorporated into the ZnO lattice. Structural characterization indicated that the Fe-doped ZnO nanorods grow along the c-axis with a hexagonal wurtzite structure and have single crystalline nature without any secondary phases or clusters of FeO or Fe3O4 observed in the samples. The Fe-doped ZnO nanorods showed room temperature (300 K) ferromagnetic magnetization versus field (M-H) hysteresis and the magnetization increases from 2.5 μemu to 9.1 μemu for Zn0.99Fe0.01O and Zn0.95Fe0.05O, respectively. Moreover, the fabricated Au/Fe-doped ZnO Schottky diode based UV photodetector achieved 2.33 A/W of responsivity and 5 s of time response. Compared to other Au/ZnO nanorods Schottky devices, the presented responsivity is an improvement by a factor of 3.9.

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  • 27.
    del Pozo, Freddy G.
    et al.
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Pfattner, Raphael
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Georgakopoulos, Stamatis
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Galindo, Sergi
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Veciana, Jaume
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Rovira, Concepcio
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Mas-Torrent, Marta
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Single Crystal-Like Performance in Solution-Coated Thin-Film Organic Field-Effect Transistors2016In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 14, p. 2379-2386Article in journal (Refereed)
    Abstract [en]

    In electronics, the field-effect transistor (FET) is a crucial cornerstone and successful integration of this semiconductor device into circuit applications requires stable and ideal electrical characteristics over a wide range of temperatures and environments. Solution processing, using printing or coating techniques, has been explored to manufacture organic field-effect transistors (OFET) on flexible carriers, enabling radically novel electronics applications. Ideal electrical characteristics, in organic materials, are typically only found in single crystals. Tiresome growth and manipulation of these hamper practical production of flexible OFETs circuits. To date, neither devices nor any circuits, based on solution-processed OFETs, has exhibited an ideal set of characteristics similar or better than todays FET technology based on amorphous silicon. Here, bar-assisted meniscus shearing of dibenzo-tetrathiafulvalene to coat-process self-organized crystalline organic semiconducting domains with high reproducibility is reported. Including these coatings as the channel in OFETs, electric field and temperature-independent charge carrier mobility and no bias stress effects are observed. Furthermore, record-high gain in OFET inverters and exceptional operational stability in both air and water are measured.

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  • 28.
    Elhadi Adam, Rania
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pirhashemi, Mahsa
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. University of Mohaghegh Ardabili, Ardabil, Iran.
    Elhag, Sami
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Habibi-Yangjeh, Aziz
    University of Mohaghegh Ardabili, Ardabil, Iran.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation2019In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 15, p. 8271-8279Article in journal (Refereed)
    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

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  • 29.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Dopamine wide range detection sensor based on modified Co3O4 nanowires electrode2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 203, p. 543-549Article in journal (Refereed)
    Abstract [en]

    Ultra-thin cobalt oxide (Co3O4) nanowires grown on gold coated glass substrates by the hydrothermal chemical deposition and have been used as a wide range dopamine potentiometric sensor. An anionic surfactant ( sodium dodecylbenzenesulfonate) was used to achieve assisted growth procedure. Moreover, a polymeric membrane containing polyvinyl chloride as plasticized polymer, p-cyclodextrin as ionophore, and potassium tetrakis (4-chlorophenyl) borate as ionic additive were immobilized on the Co3O4 nanostructures through electrostatic adsorption method. X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy were used to characterize the electrodes while ultraviolet-visible absorption was used to investigate the band gap of the Co3O4 nanostructures. The structural characterization showed a cubic crystalline, pure phase, and nanowires morphology of the Co3O4. However, the morphology is altered when the surfactant concentration has been changed. The Co3O4 chemical modified electrodes were used in potentiometric measurements for dopamine in a 10(-2) M acetic acid/sodium acetate solution having a pH of 5.45. For dopamine range from 10(-9) M to 10(-2) M, the potential response of the sensor electrode was linear with a slope of 52 mV/decade. The wide range and high sensitivity of the modified Co3O4 nanowires based sensor for dopamine is attributed to the defects on the metal oxide that is dictated by the used surfactant along with the high surface area-to-volume ratio.

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  • 30.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties2016In: Sensors, E-ISSN 1424-8220, Vol. 16, no 2Article in journal (Refereed)
    Abstract [en]

    In this paper, we show that the possibility of using polyethylene glycol (EG) as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs). EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS) suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL) and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10(-6) M to 10(-3) M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices.

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  • 31.
    Fabiano, Simone
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Weverberghs, Eric
    University of Mons-UMONS, Belgium.
    Gerbaux, Pascal
    University of Mons-UMONS, Belgium.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Poly(ethylene imine) impurities induce n-doping reaction in organic (semi)conductors2014In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 26, no 34, p. 6000-6006Article in journal (Refereed)
    Abstract [en]

    Volatile impurities contained in polyethyleneimine (PEI), and identified as ethyleneimine dimers and trimers, are reported. These N-based molecules show a strong reducing character, as demonstrated by the change in electrical conductivity of organic (semi) conductors exposed to the PEI vapor. The results prove that electron transfer rather than a dipole effect at the electrode interface is the origin of the work-function modification by the PEI-based layers.

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  • 32.
    Gaceur, Meriem
    et al.
    Aix Marseille University, France.
    Ben Dkhil, Sadok
    Aix Marseille University, France.
    Duche, David
    Aix Marseille University, France.
    Bencheikh, Fatima
    Aix Marseille University, France.
    Simon, Jean-Jacques
    Aix Marseille University, France.
    Escoubas, Ludovic
    Aix Marseille University, France.
    Mansour, Mahdi
    University of Jaume 1, Spain.
    Guerrero, Antonio
    University of Jaume 1, Spain.
    Garcia-Belmonte, Germa
    University of Jaume 1, Spain.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Dachraoui, Walid
    Aix Marseille University, France.
    Karim Diallo, Abdou
    Aix Marseille University, France.
    Videlot-Ackermann, Christine
    Aix Marseille University, France.
    Margeat, Olivier
    Aix Marseille University, France.
    Ackermann, Joerg
    Aix Marseille University, France.
    Ligand-Free Synthesis of Aluminum-Doped Zinc Oxide Nanocrystals and their Use as Optical Spacers in Color-Tuned Highly Efficient Organic Solar Cells2016In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 2, p. 243-253Article in journal (Refereed)
    Abstract [en]

    The color of polymer solar cells using an opaque electrode is given by the reflected light, which depends on the composition and thickness of each layer of the device. Metal-oxide-based optical spacers are intensively studied in polymer solar cells aiming to optimize the light absorption. However, the low conductivity of materials such as ZnO and TiO2 limits the thickness of such optical spacers to tenths of nanometers. A novel synthesis route of cluster-free Al-doped ZnO (AZO) nanocrystals (NCs) is presented for solution processing of highly conductive layers without the need of temperature annealing, including thick optical spacers on top of polymer blends. The processing of 80 nm thick optical spacers based on AZO nanocrystal solutions on top of 200 nm thick polymer blend layer is demonstrated leading to improved photocurrent density of 17% compared to solar cells using standard active layers of 90 nm in combination with thin ZnO-based optical spacers. These AZO NCs also open new opportunities for the processing of high-efficiency color tuned solar cells. For the first time, it is shown that applying solution-processed thick optical spacer with polymer blends of different thicknesses can process solar cells of similar efficiency over 7% but of different colors.

  • 33.
    Ghorbani Shiraz, Hamid
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ullah Khan, Zia
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Pere, Daniel
    IMRA Europe SAS, France.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Coppel, Yannick
    Univ Toulouse, France.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Chmielowski, Radoslaw
    IMRA Europe SAS, France.
    Kahn, Myrtil L.
    Univ Toulouse, France.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    3R-TaS2 as an Intercalation-Dependent Electrified Interface for Hydrogen Reduction and Oxidation Reactions2022In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 126, no 40, p. 17056-17065Article in journal (Refereed)
    Abstract [en]

    Hydrogen technology, as a future breakthrough for the energy industry, has been defined as an environmentally friendly, renewable, and high-power energy carrier. The green production of hydrogen, which mainly relies on electrocatalysts, is limited by the high cost and/ or the performance of the catalytic system. Recently, studies have been conducted in search of bifunctional electrocatalysts accelerating both the hydrogen evolution reaction (HER) and the hydrogen oxidation reaction (HOR). Herein, we report the investigation of the high efficiency bifunctional electrocatalyst TaS2 for both the HER and the HOR along with the asymmetric effect of inhibition by organic intercalation. The linear organic agent, to boost the electron donor property and to ease the process of intercalation, provides a higher interlayer gap in the tandem structure of utilized nanosheets. XRD and XPS data reveal an increase in the interlayer distance of 22%. The HER and the HOR were characterized in a Pt group metal-free electrochemical system. The pristine sample shows a low overpotential of -0.016 Vat the onset. The intercalated sample demonstrates a large shift in its performance for the HER. It is revealed that the intercalation is a potential key strategy for tuning the performance of this family of catalysts. The inhibition of the HER by intercalation is considered as the increase in the operational window of a water-based electrolyte on a negative electrode, which is relevant to technologies of electrochemical energy storage.

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  • 34.
    Henry, Anne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Leone, Stefano
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kordina, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, J. Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Epitaxial growth on on-axis substrates2012In: Silicon Carbide Epitaxy / [ed] Francesco La Via, Kerala, India: Research Signpost, 2012, p. 97-119Chapter in book (Refereed)
    Abstract [en]

    SiC epitaxial growth using the Chemical Vapour Deposition (CVD) technique on nominally on-axis substrate is presented. Both standard and chloride-based chemistry have been used with the aim to obtain high quality layers suitable for device fabrication. Both homoepitaxy (4H on 4H) and heteroepitaxy (3C on hexag onal substrate) are addressed.

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    Epitaxial growth on on-axis substrates
  • 35.
    Hussain Ibupoto, Zafar
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamal, N
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    A potentiometric immunosensor based on silver nanoparticles decorated ZnO nanotubes, for the selective detection of d-dimer2013In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 182, p. 104-111Article in journal (Refereed)
    Abstract [en]

    In this study, a new, simple, fast and highly sensitive potentiometric immunosensor for the selective detection of d-dimer is developed using silver nanoparticles decorated ZnO nanotubes. The d-dimer is a biomarker and found at high levels in the human body when it suffers from deep vein thrombosis (DVT) disorders. ZnO nanotubes were obtained by the chemical etching of nanorods using a hydrothermal method. The silver nanoparticles were deposited on the ZnO nanotubes using an electrodepositing technique. The structure and the composition characterization was measured by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques respectively. The ZnO nanorods are perpendicular to the substrate with uniform distribution. The etching of the nanorods into nanotubes is almost complete and the nanotubes are fully covered with silver nanoparticles. The mouse anti human d-dimer antibody was immobilized on the silver nanoparticles decorated ZnO nanotubes for the selective detection of d-dimer. The potentiometric immunosensor has shown a highly sensitive and linear response for the wide range of 1.00 x 10(-5)-1.00 x 10(0) mu g/ml d-dimer concentrations prepared in the phosphate buffer solution of pH 7.4. The presented d-dimer biosensor exhibited a detection limit of 1.00 x 10(-6) mu g/ml. The antibody immobilized immunosensor presents a fast response time of less than 5 s with acceptable selectivity, reproducibility and storage stability. The observed performance of the developed immunosensor demonstrates the high usability for the selective detection of the d-dimer from clinical and real samples.

  • 36.
    Hussain Ibupoto, Zafar
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Khun, K
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Low temperature synthesis of seed mediated CuO bundle of nanowires, their structural characterisation and cholesterol detection2013In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 33, no 7, p. 3889-3898Article in journal (Refereed)
    Abstract [en]

    In this study, we have successfully synthesised CuO bundle of nanowires using simple, cheap and low temperature hydrothermal growth method. The growth parameters such as precursor concentration and time for duration of growth were optimised. The field emission scanning electron microscopy (FESEM) has demonstrated that the CuO bundles of nanowires are highly dense, uniform and perpendicularly oriented to the substrate. The high resolution transmission electron microscopy (HRTEM) has demonstrated that the CuO nanostructures consist of bundle of nanowires and their growth pattern is along the [010] direction. The X-ray diffraction (XRD) technique described that CuO bundle of nanowires possess the monoclinic crystal phase. The surface and chemical composition analyses were carried out with X-ray photoelectron spectroscopy (XPS) technique and the obtained results suggested the pure crystal state of CuO nanostructures. In addition, the CuO nanowires were used for the cholesterol sensing application by immobilising the cholesterol oxidase through electrostatic attraction. The infrared reflection absorption spectroscopy study has also revealed that CuO nanostructures are consisting of only Cu-O bonding and has also shown the possible interaction of cholesterol oxidase with the sharp edge surface of CuO bundle of nanowires. The proposed cholesterol sensor has demonstrated the wide range of detection of cholesterol with good sensitivity of 33.88 +/- 0.96 mV/decade. Moreover, the CuO bundle of nanowires based sensor electrode has revealed good repeatability, reproducibility, stability, selectivity and a fast response time of less than 10 s. The cholesterol sensor based on the immobilised cholesterol oxidase has good potential applicability for the determination of cholesterol from the human serum and other biological samples.

  • 37.
    Hussain Ibupoto, Zafar
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Khun, K
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    AlSalhi, M S.
    King Saud University, Saudi Arabia .
    Atif, M
    King Saud University, Saudi Arabia .
    Ansari, Anees A:
    King Saud University, Saudi Arabia .
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Well aligned ZnO nanorods growth on the gold coated glass substrate by aqueous chemical growth method using seed layer of Fe3O4 and Co3O4 nanoparticles2013In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 368, p. 39-46Article in journal (Refereed)
    Abstract [en]

    In this study, Fe3O4 and Co3O4 nanoparticles were prepared by co-precipitation method and sol-gel method respectively. The synthesised nanoparticles were characterised by X-ray diffraction [XRD] and Raman spectroscopy techniques. The obtained results have shown the nanocrystalline phase of obtained Fe3O4 and Co3O4 nanoparticles. Furthermore, the Fe3O4 and Co3O4 nanoparticles were used as seed layer for the fabrication of well-aligned ZnO nanorods on the gold coated glass substrate by aqueous chemical growth method. Scanning electron microscopy (SEM), high resolution transmission electron microscopy [HRTEM], as well as XRD and energy dispersive X-ray techniques were used for the structural characterisation of synthesised ZnO nanorods. This study has explored highly dense, uniform, well-aligned growth pattern along 0001 direction and good crystal quality of the prepared ZnO nanorods. ZnO nanorods are only composed of Zn and O atoms. Moreover, X-ray photoelectron spectroscopy was used for the chemical analysis of fabricated ZnO nanorods. In addition, the structural characterisation and the chemical composition study and the optical investigation were carried out for the fabricated ZnO nanorods and the photoluminescence [PL] spectrum have shown strong ultraviolet (UV) peak at 381 nm for Fe3O4 nanoparticles seeded ZnO nanorods and the PL spectrum for ZnO nanorods grown with the seed layer of Co3O4 nanoparticles has shown a UV peak at 382 nm. The green emission and orange/red peaks were also observed for ZnO nanorods grown with both the seed layers. This study has indicated the fabrication of well aligned ZnO nanorods using the one inorganic nanomaterial on other inorganic nanomaterial due to their similar chemistry.

  • 38.
    Hussain, Mushtaque
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Synthesis of Three Dimensional Nickel Cobalt Oxide Nanoneedles on Nickel Foam, Their Characterization and Glucose Sensing Application2014In: Sensors, E-ISSN 1424-8220, Vol. 14, no 3, p. 5415-5425Article in journal (Refereed)
    Abstract [en]

    In the present work, NiCo2O4 nanostructures are fabricated in three dimensions (3D) on nickel foam by the hydrothermal method. The nanomaterial was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The nanostructures exhibit nanoneedle-like morphology grown in 3D with good crystalline quality. The nanomaterial is composed of nickel, cobalt and oxygen atoms. By using the favorable porosity of the nanomaterial and the substrate itself, a sensitive glucose sensor is proposed by immobilizing glucose oxidase. The presented glucose sensor has shown linear response over a wide range of glucose concentrations from 0.005 mM to 15 mM with a sensitivity of 91.34 mV/decade and a fast response time of less than 10 s. The NiCo2O4 nanostructures-based glucose sensor has shown excellent reproducibility, repeatability and stability. The sensor showed negligible response to the normal concentrations of common interferents with glucose sensing, including uric acid, dopamine and ascorbic acid. All these favorable advantages of the fabricated glucose sensor suggest that it may have high potential for the determination of glucose in biological samples, food and other related areas.

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  • 39.
    Iandolo, Donata
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ravichandran, Akhilandeshwari
    School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Wen, Feng
    School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore.
    Chan, Jerry K Y
    Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Teoh, Swee-Hin
    School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore.
    Simon, Daniel T
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Development and Characterization of Organic Electronic Scaffolds for Bone Tissue Engineering2016In: Advanced Healthcare Materials, ISSN 2192-2640, E-ISSN 2192-2659, Vol. 5, no 12, p. 1505-1512Article in journal (Refereed)
    Abstract [en]

    Bones have been shown to exhibit piezoelectric properties, generating electrical potential upon mechanical deformation and responding to electrical stimulation with the generation of mechanical stress. Thus, the effects of electrical stimulation on bone tissue engineering have been extensively studied. However, in bone regeneration applications, only few studies have focused on the use of electroactive 3D biodegradable scaffolds at the interphase with stem cells. Here a method is described to combine the bone regeneration capabilities of 3D-printed macroporous medical grade polycaprolactone (PCL) scaffolds with the electrical and electrochemical capabilities of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). PCL scaffolds have been highly effective in vivo as bone regeneration grafts, and PEDOT is a leading material in the field of organic bioelectronics, due to its stability, conformability, and biocompatibility. A protocol is reported for scaffolds functionalization with PEDOT, using vapor-phase polymerization, resulting in a conformal conducting layer. Scaffolds' porosity and mechanical stability, important for in vivo bone regeneration applications, are retained. Human fetal mesenchymal stem cells proliferation is assessed on the functionalized scaffolds, showing the cytocompatibility of the polymeric coating. Altogether, these results show the feasibility of the proposed approach to obtain electroactive scaffolds for electrical stimulation of stem cells for regenerative medicine.

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  • 40.
    Ibupoto, Zafar Hussain
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    AlSalhi, M. S.
    King Saud University, Riyadh, Saudi Arabia .
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    The Synthesis of NiO/TiO2 Heterostructures and Their Valence Band Offset Determination2014In: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, no 928658Article in journal (Refereed)
    Abstract [en]

    In this work, a heterojunction based on p-type NiO/n-type TiO2 nanostructures has been prepared on the fluorine doped tin oxide (FTO) glass substrate by hydrothermal method. Scanning electron microscopy (SEM) and X-Ray diffraction techniques were used for the morphological and crystalline arrays characterization. The X-ray photoelectron spectroscopy was employed to determine the valence-band offset (VBO) of the NiO/TiO2 heterojunction prepared on FTO glass substrate. The core levels of Ni 2p and Ti 2p were utilized to align the valence-band offset of p-type NiO/n-type TiO2 heterojunction. The valence band offset was found to be similar to 0.41 eV and the conduction band was calculated about similar to 0.91 eV. The ratio of conduction band offset and the valence-band offset was found to be 2.21.

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  • 41.
    Ibupoto, Zafar Hussain
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Synthesis of Novel CuO Nanosheets and Their Non-Enzymatic Glucose Sensing Applications2013In: Sensors, E-ISSN 1424-8220, Vol. 13, no 6, p. 7926-7938Article in journal (Refereed)
    Abstract [en]

    Abstract: In this study, we have developed a sensitive and selective glucose sensor using novel CuO nanosheets which were grown on a gold coated glass substrate by a low temperature growth method. X-ray differaction (XRD) and scanning electron microscopy (SEM) techniques were used for the structural characterization of CuO nanostructures. CuO nanosheets are highly dense, uniform, and exhibited good crystalline array structure. X-ray photoelectron spectroscopy (XPS) technique was applied for the study of chemical composition of CuO nanosheets and the obtained information demonstrated pure phase CuO nanosheets. The novel CuO nanosheets were employed for the development of a sensitive and selective non-enzymatic glucose sensor. The measured sensitivity and a correlation coefficient are in order 5.20 × 102 µA/mMcm2 and 0.998, respectively. The proposed sensor is associated with several advantages such as low cost, simplicity, high stability, reproducibility and selectivity for the quick detection of glucose.

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  • 42.
    Ibupoto, Zafar Hussain
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    A Potentiometric Biosensor for the Detection of Notch 3 Using Functionalized ZnO Nanorods2014In: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 14, no 9, p. 6704-6710Article in journal (Refereed)
    Abstract [en]

    The notch signalling plays a vital and radical role for the activity of cellular proliferation, differentiation and apoptosis. In this study, for the first time a particular biosensor is developed for the detection of notch 3. ZnO nanorods were fabricated on the gold coated glass substrate by hydrothermal method and afterwards were decorated with the gold nanoparticles by electrodepositing technique. Scanning electron microscopy (SEM) has shown the perpendicular to the substrate growth pattern of ZnO nanorods. X-ray diffraction (XRD) studies showed the c-axis oriented growth direction with wurtzite crystal structure of ZnO nanorods. X-ray Photoelectron Spectroscopy (XPS) and energy dispersive X-ray (EDX) techniques have shown the presence of Zn, O and Au atoms in the prepared functional material. Furthermore, the anti-notch 3 was physically adsorbed on the gold nanoparticles functionalized ZnO nanorods. The developed potentiometric immunosensor has shown response to the wide range of notch 3 molecules. The detected range included 1.00 x 10(-5)-1.50 x 10(0) mu g/mL with a sensitivity of 23.15 +/- 0.31 mV/decade. The analytical parameters including reproducibility, stability, and selectivity were also investigated and the observed results indicate the acceptable performance of the notch 3 biosensor. Moreover, the proposed notch 3 biosensor exhibited a fast response time of 10 s.

  • 43.
    Ibupoto, Zafar Hussain
    et al.
    Division of Material Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden; Dr. M.A Kazi Institute of Chemistry University of Sindh Jamshoro, Sindh, Pakistan.
    Tahira, Aneela
    Division of Material Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Tang, PengYi
    Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, Catalonia, Spain; Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià del Besòs, Barcelona, Catalonia, Spain.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Morante, Joan Ramon
    Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià del Besòs, Barcelona, Catalonia, Spain.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Arbiol, Jordi
    Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, Catalonia, Spain; ICREA, Pg. Lluís Companys 23, Barcelona, Catalonia, Spain.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vomiero, Alberto
    Division of Material Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    MoSx@NiO Composite Nanostructures: An Advanced Nonprecious Catalyst for Hydrogen Evolution Reaction in Alkaline Media2019In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 29, no 7, article id 1807562Article in journal (Refereed)
    Abstract [en]

    The design of the earth-abundant, nonprecious, efficient, and stable electrocatalysts for efficient hydrogen evolution reaction (HER) in alkaline media is a hot research topic in the field of renewable energies. A heterostructured system composed of MoSx deposited on NiO nanostructures (MoSx@NiO) as a robust catalyst for water splitting is proposed here. NiO nanosponges are applied as cocatalyst for MoS2 in alkaline media. Both NiO and MoS2@NiO composites are prepared by a hydrothermal method. The NiO nanostructures exhibit sponge-like morphology and are completely covered by the sheet-like MoS2. The NiO and MoS2 exhibit cubic and hexagonal phases, respectively. In the MoSx@NiO composite, the HER experiment in 1 m KOH electrolyte results in a low overpotential (406 mV) to produce 10 mA cm(-2) current density. The Tafel slope for that case is 43 mV per decade, which is the lowest ever achieved for MoS2-based electrocatalyst in alkaline media. The catalyst is highly stable for at least 13 h, with no decrease in the current density. This simple, cost-effective, and environmentally friendly methodology can pave the way for exploitation of MoSx@NiO composite catalysts not only for water splitting, but also for other applications such as lithium ion batteries, and fuel cells.

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  • 44.
    Jiang, Sheng
    et al.
    East China Normal Univ, Peoples R China.
    Xiong, Shaobing
    East China Normal Univ, Peoples R China.
    Dong, Wei
    East China Normal Univ, Peoples R China.
    Li, Danqin
    East China Normal Univ, Peoples R China.
    Yan, Yuting
    East China Normal Univ, Peoples R China.
    Jia, Menghui
    East China Normal Univ, Peoples R China.
    Dai, Yannan
    East China Normal Univ, Peoples R China.
    Zhao, Qingbiao
    East China Normal Univ, Peoples R China.
    Jiang, Kai
    East China Normal Univ, Peoples R China.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ding, Liming
    Natl Ctr Nanosci & Technol, Peoples R China.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sun, Zhenrong
    East China Normal Univ, Peoples R China.
    Bao, Qinye
    East China Normal Univ, Peoples R China; Shanxi Univ, Peoples R China.
    Constructing Chromium Multioxide Hole-Selective Heterojunction for High-Performance Perovskite Solar Cells2022In: Advanced Science, E-ISSN 2198-3844, Vol. 9, no 30, article id 2203681Article in journal (Refereed)
    Abstract [en]

    Perovskite solar cells (PSCs) suffer from significant nonradiative recombination at perovskite/charge transport layer heterojunction, seriously limiting their power conversion efficiencies. Herein, solution-processed chromium multioxide (CrOx) is judiciously selected to construct a MAPbI(3)/CrOx/Spiro-OMeTAD hole-selective heterojunction. It is demonstrated that the inserted CrOx not only effectively reduces defect sites via redox shuttle at perovskite contact, but also decreases valence band maximum (VBM)-HOMO offset between perovskite and Spiro-OMeTAD. This will diminish thermionic losses for collecting holes and thus promote charge transport across the heterojunction, suppressing both defect-assisted recombination and interface carrier recombination. As a result, a remarkable improvement of 21.21% efficiency with excellent device stability is achieved compared to 18.46% of the control device, which is among the highest efficiencies for polycrystalline MAPbI(3) based n-i-p planar PSCs reported to date. These findings of this work provide new insights into novel charge-selective heterojunctions for further enhancing efficiency and stability of PSCs.

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  • 45.
    Jiang, Sheng
    et al.
    East China Normal Univ, Peoples R China.
    Xiong, Shaobing
    East China Normal Univ, Peoples R China; Fudan Univ, Peoples R China.
    Wu, Hongbo
    Donghua Univ, Peoples R China.
    Zhao, Dongyang
    East China Normal Univ, Peoples R China.
    You, Xiaomeng
    East China Normal Univ, Peoples R China.
    Xu, Yehui
    East China Normal Univ, Peoples R China.
    Jia, Menghui
    East China Normal Univ, Peoples R China.
    Bai, Wei
    East China Normal Univ, Peoples R China.
    Ma, Zaifei
    Donghua Univ, Peoples R China.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Yao, Yefeng
    East China Normal Univ, Peoples R China.
    Sun, Zhenrong
    East China Normal Univ, Peoples R China.
    Bao, Qinye
    East China Normal Univ, Peoples R China; Fudan Univ, Peoples R China; Shanxi Univ, Peoples R China.
    In Situ Reconstruction of Hole-Selective Perovskite Heterojunction with Graded Energetics Toward Highly Efficient and Stable Solar Cells2023In: Advanced Energy Materials, ISSN 1614-6832, E-ISSN 1614-6840, Vol. 13, no 27, article id 2300983Article in journal (Refereed)
    Abstract [en]

    Perovskite solar cells (PSCs) have demonstrated a high power conversion efficiency, however, the large energy loss due to non-radiative recombination is the main challenge for further performance enhancement. Here, a surface treatment strategy is developed by heat-induced decomposition of a thin interlayer 2,7-Naphthaleneditriflate (NAP) to in situ reconstruct perovskite energetics. It is verified that the reconstructed perovskite surface energetics match better with the upper hole transport layer compared to the intrinsic condition. Spontaneous generation of n/n(-) homojunctions between the perovskite film bulk and the surface region promotes hole extraction, enhancing built-in electric field, and thus significantly suppresses charge recombination at such perovskite hole-selective heterojunctions. Moreover, the surface decomposed fluorine-rich complexes passivate the defects and improve the crystallinity of the perovskite film. These advantages are confirmed by a remarkably improved efficiency from 20.52% for the control device to 23.37% for the treated one with excellent stability. The work provides a promising approach of in situ reconstructing perovskite surface and interface for the design of highly efficient and stable PSCs.

  • 46.
    Karlsson, Roger
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Herland, Anna
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Hamedi, Mahiar
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wigenius, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Åslund, Andreas
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Iron-Catalyzed Polymerization of Alkoxysulfonate-Functionalized 3,4-Ethylenedioxythiophene Gives Water-Soluble Poly(3,4-ethylenedioxythiophene) of High Conductivity2009In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 21, no 9, p. 1815-1821Article in journal (Refereed)
    Abstract [en]

    Chemical polymerization of a 3,4-ethylenedioxythiophene derivative bearing a sulfonate group (EDOTS) is reported. The polymer, PEDOT-S, is fully water-soluble and has been produced by polymerizing EDOT-S in water, using Na2S2O8 and a catalytic amount of FeCl3. Elemental analysis and XPS measurements indicate that PEDOT-S is a material with a substantial degree of self-doping, but also contains free sulfate ions as charge-balancing counterions of the oxidized polymer. Apart from self-doping PEDOT-S, the side chains enable full water solubility of the material; DLS studies show an average cluster size of only 2 nm. Importantly, the solvation properties of the PEDOT-S are reflected in spin-coated films, which show a surface roughness of 1.2 nm and good conductivity (12 S/cm) in ambient conditions. The electro-optical properties of this material are shown with cyclic voltammetry and spectroelectrochemical experiment reveals an electrochromic contrast (similar to 48% at lambda(max) = 606 nm).

  • 47.
    Kesters, Jurgen
    et al.
    Hasselt University, Belgium.
    Govaerts, Sanne
    Hasselt University, Belgium.
    Pirotte, Geert
    Hasselt University, Belgium.
    Drijkoningen, Jeroen
    Hasselt University, Belgium.
    Chevrier, Michele
    University of Montpellier, France; University of Mons UMONS, Belgium.
    Van den Brande, Niko
    Vrije University of Brussel, Belgium.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Van Mele, Bruno
    Vrije University of Brussel, Belgium.
    Lutsen, Laurence
    Hasselt University, Belgium.
    Vanderzande, Dirk
    Hasselt University, Belgium.
    Manca, Jean
    Hasselt University, Belgium.
    Clement, Sebastien
    University of Montpellier, France.
    Von Hauff, Elizabeth
    Vrije University of Amsterdam, Netherlands.
    Maes, Wouter
    Hasselt University, Belgium.
    High-Permittivity Conjugated Polyelectrolyte Interlayers for High-Performance Bulk Heterojunction Organic Solar Cells2016In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, no 10, p. 6309-6314Article in journal (Refereed)
    Abstract [en]

    Conjugated polyelectrolyte (CPE) interfacial layers present a powerful way to boost the I-V characteristics of organic photovoltaics. Nevertheless, clear guidelines with respect to the structure of high-performance interlayers are still lacking. In this work, impedance spectroscopy is applied to probe the dielectric permittivity of a series of polythiophene-based CPEs. The presence of ionic pendant groups grants the formation of a capacitive double layer, boosting the charge extraction and device efficiency. A counteracting effect is the diminishing affinity with the underlying photoactive layer. To balance these two effects, we found copolymer structures containing nonionic side chains to be beneficial.

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  • 48.
    Kharlamova, Marianna V.
    et al.
    University of Vienna, Austria Moscow MV Lomonosov State University, Russia .
    Sauer, Markus
    University of Vienna, Austria .
    Saito, Takeshi
    National Institute Adv Ind Science and Technology, Japan .
    Krause, Stefan
    BESSY II, Germany .
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Yanagi, Kazuhiro
    Tokyo Metropolitan University, Japan .
    Pichler, Thomas
    University of Vienna, Austria .
    Shiozawa, Hidetsugu
    University of Vienna, Austria .
    Inner tube growth properties and electronic structure of ferrocene-filled large diameter single-walled carbon nanotubes2013In: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 250, no 12, p. 2575-2580Article in journal (Refereed)
    Abstract [en]

    We study the filling of single-walled carbon nanotubes (SW- CNTs) with ferrocene molecules. Using e-DIPS SWCNTs with a mean diameter of 1.7nm, we obtain a filling factor as high as 90%. At elevated temperatures in high vacuum the filled SWCNTs are transformed to double-walled carbon nanotubes (DWCNTs). Temperature dependence of inner tube growth is investigated by Raman spectroscopy. The electronic properties of the obtained nanostructures are studied by X-ray photoelectron spectroscopy and near edge X-ray absorption fine structure spectroscopy. It is found that the growth temperature is higher for larger diameter inner tubes. It is demonstrated that ferrocene filling leads to electron doping of SWCNTs.

  • 49.
    Khun, Kimleang
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Mansor, N. A.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    An Electrochemical Dopamine Sensor Based on the ZnO/CuO Nanohybrid Structures2014In: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 14, no 9, p. 6646-6652Article in journal (Refereed)
    Abstract [en]

    The selective detection of dopamine (DA) is of great importance in the modern medicine because dopamine is one of the main regulators in human behaviour. In this study, ZnO/CuO nanohybrid structures, grown on the gold coated glass substrate, have been investigated as a novel electrode material for the electrochemical detection of dopamine. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were used for the material characterization and the obtained results are in good agreement. The selective determination of dopamine was demonstrated by cyclic voltammetry (CV) and amperometric experiments. The amperometric response was linear for dopamine concentrations between 1.0 x 10(-3) and 8.0 mM with a sensitivity of 90.9 mu A mM(-1) cm(-2). The proposed dopamine biosensor is very stable, selective over common interferents as glucose, uric acid and ascorbic acid, and also good reproducibility was observed for seven electrodes. Moreover, the dopamine sensor exhibited a fast response time of less than 10 s. The wide range and acceptable sensitivity of the presented dopamine sensor provide the possible application in analysing the dopamine from the real samples.

  • 50.
    Khun, Kimleang
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Danielsson, Bengt
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    A Selective Potentiometric Copper (II) Ion Sensor Based on the Functionalized ZnO Nanorods2014In: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 14, no 9, p. 6723-6731Article in journal (Refereed)
    Abstract [en]

    In this work, ZnO nanorods were hydrothermally grown on the gold-coated glass substrate and characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. The ZnO nanorods were functionalized by two different approaches and performance of the sensor electrode was monitored. Fourier transform infrared spectroscopy (FTIR) was carried out for the confirmation of interaction between the ionophore molecules and ZnO nanorods. In addition to this, the surface of the electrode was characterized by X-ray photoelectron spectroscopy (XPS) showing the chemical and electronic state of the ionophore and ZnO nanorod components. The ionophore solution was prepared in the stabilizer, poly vinyl chloride (PVC) and additives, and then functionalized on the ZnO nanorods that have shown the Nernstian response with the slope of 31 mV/decade. However, the Cu2+ ion sensor was fabricated only by immobilizing the selective copper ion ionophore membrane without the use of PVC, plasticizers, additives and stabilizers and the sensor electrode showed a linear potentiometric response with a slope of 56.4 mV/decade within a large dynamic concentration range (from 1.0 x 10(-6) to 1.0 x 10(-1) M) of copper (II) nitrate solutions. The sensor showed excellent repeatability and reproducibility with response time of less than 10 s. The negligible response to potentially interfering metal ions such as calcium (Ca2+), magnesium (Mg2+), potassium (K+), iron (Fe3+), zinc (Zn2+), and sodium (Na+) allows this sensor to be used in biological studies. It may also be used as an indicator electrode in the potentiometric titration.

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