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  • 301.
    Willfahrt, Andreas
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Stuttgart Media Univ, Germany.
    Steiner, Erich
    Stuttgart Media Univ, Germany.
    Hoetzel, Jonas
    Stuttgart Media Univ, Germany.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Printable acid-modified corn starch as non-toxic, disposable hydrogel-polymer electrolyte in supercapacitors2019In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 125, no 7, article id 474Article in journal (Refereed)
    Abstract [en]

    Corn starch and citric acid, two low-cost and abundant materials, were used for establishing a novel screen printable hydrogel for printed electronics applications. Corn starch was modified with citric acid by melt-blending; the so obtained thermoplastic starch was ground to powder and added to a water-starch suspension. Ultrasonication was used to prepare hydrogels of different citric acid concentrations. The most promising hydrogel contained 10% citric acid by weight, provided an ionic conductivity of (2.30 +/- 0.07)mScm(-1) and appropriate rheological properties for screen and stencil printing. The hydrogel shows superb printability and prolonged stability against degradation. The corn starch hydrogel was used as printable gel polymer electrolyte in fully printed supercapacitors. The specific capacitance of the printed supercapacitor reached 54Fg(-1). The printable hydrogel-polymer electrolyte is easy to produce without in-depth chemical knowledge, is based on widely used and non-toxic materials, and may be used as a functional layer in other printed electronics applications such as printed batteries.

    The full text will be freely available from 2020-06-22 07:23
  • 302.
    Wilson, Peter M.
    et al.
    University of Nebraska, USA.
    Zobel, Adam
    University of Nebraska, USA.
    Zaitouna, Anita J.
    University of Nebraska, USA.
    Lipatov, Alexey
    University of Nebraska, USA.
    Schubert, Eva
    University of Nebraska, USA.
    Hofmann, Tino
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. University of Nebraska, USA.
    Schubert, Mathias
    University of Nebraska, USA.
    Lai, Rebecca
    University of Nebraska, USA.
    Sinitskii, Alexander
    University of Nebraska, USA; National University of Science and Technology MISIS, Russia.
    Solution-stable anisotropic carbon nanotube/graphene hybrids based on slanted columnar thin films for chemical sensing2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 68, p. 63235-63240Article in journal (Refereed)
    Abstract [en]

    Slanted columnar thin films (SCTFs) are promising anisotropic nano-structures for applications in optical sensing and chemical separation. However, the wide use of SCTFs is significantly limited by their poor mechanical properties and structural stability, especially in liquid media. In this work, we demonstrate the fabrication of solution-stable carbon nanotube (CNT)/graphene hybrid structures based on cobalt SCTFs. The CNT/graphene hybrid structures were synthesized through the use of a titanium underlayer for Co slanted nanopillars as a chemical vapor deposition catalyst, which allows simultaneous growth of CNTs at the Co/Ti interface and three-dimensional graphene over the surface of cobalt. Importantly, the CNT/graphene hybrid structures retain the anisotropy of the parent Co SCTFs and thus remain suitable for optical sensing. Graphene/CNT modification of Co SCTFs not only improves their stability in solutions but also enables their functionalization with pyrene-modified DNA probes, which can be monitored in real time by in situ ellipsometry measurements. In turn, the solution-stable DNA-modified SCTFs may find a wide range of applications in biosensing. The described synthetic approach that allows simultaneous growth of CNTs and graphene by engineering Co/Ti interfaces may also be applied to the fabrication of other kinds of complex CNT/graphene hybrid materials.

  • 303.
    Wing Cheung, Mak
    et al.
    National University of Singapore.
    Cheung, Kwan Yee
    National University of Singapore.
    Trau, Dieter
    National University of Singapore.
    Influence of Different Polyelectrolytes on Layer-by-Layer Microcapsule Properties: Encapsulation Efficiency and Colloidal and Temperature Stability2008In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 20, no 17, p. 5475-5484Article in journal (Refereed)
    Abstract [en]

    The fabrication of colloidal and temperature stable microcapsules for encapsulation of biomolecules based on matrix-assisted layer-by-layer (LbL) encapsulation by polyelectrolyte self-assembly has been demonstrated. In brief, the process is based on the emulsification of a hydrogel in warm oil for microdroplet formation. The hydrogel acts as a matrix for the later encapsulation process and can be loaded with biomolecules. After microdroplets of, for example, protein loaded hydrogel are formed by emulsification, cooling leads to solidification of the droplets to form microbeads, followed by encapsulation of the hydrogel microbeads with polyelectrolyte multilayers through an LbL self-assembly process to form polymeric capsules. Colloidal stability, encapsulation efficiency, and temperature stability of the LbL hydrogel microcapsules composed from different polyelectrolytes with various ionic strengths and charge densities have been studied. Microcapsules fabricated with strong polyelectrolytes showed better colloidal stability, while microcapsules fabricated with weak polyelectrolytes showed better encapsulation efficiency and temperature stability. After temperature treatment, microcapsules fabricated with different polyelectrolytes exhibited different morphological changes from complete rupturing over broken microcapsules with deformed hollow shells to intact microcapsules. Among all the studied polyelectrolyte pairs, the PAH/PSS polyelectrolyte system was found to be the best material to fabricate microcapsules with good colloidal and temperature stability and high encapsulation efficiency. Microcapsules with PSS as the outermost layer remained similar in size after temperature treatment, while microcapsules with PAH as the outermost layer shrunk by 76% in capsule volume. The present study provides a detailed overview on properties and design of LbL microcapsules as a function of polyelectrolyte materials and layer number. As a result of the versatility of loading LbL hydrogel microcapsules with various biomolecules or mixtures, potential applications are in the fields of diagnostics, drug delivery, and life sciences.

  • 304.
    Wofford, Joseph M.
    et al.
    Paul Drude Institute Festkorperelektron, Germany.
    Nakhaie, Siamak
    Paul Drude Institute Festkorperelektron, Germany.
    Krause, Thilo
    Paul Drude Institute Festkorperelektron, Germany.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Ramsteiner, Manfred
    Paul Drude Institute Festkorperelektron, Germany.
    Hanke, Michael
    Paul Drude Institute Festkorperelektron, Germany.
    Riechert, Henning
    Paul Drude Institute Festkorperelektron, Germany.
    Lopes, J. Marcelo J.
    Paul Drude Institute Festkorperelektron, Germany.
    A hybrid MBE-based growth method for large-area synthesis of stacked hexagonal boron nitride/graphene heterostructures2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 43644Article in journal (Refereed)
    Abstract [en]

    Van der Waals heterostructures combining hexagonal boron nitride (h-BN) and graphene offer many potential advantages, but remain difficult to produce as continuous films over large areas. In particular, the growth of h-BN on graphene has proven to be challenging due to the inertness of the graphene surface. Here we exploit a scalable molecular beam epitaxy based method to allow both the h-BN and graphene to form in a stacked heterostructure in the favorable growth environment provided by a Ni(111) substrate. This involves first saturating a Ni film on MgO(111) with C, growing h-BN on the exposed metal surface, and precipitating the C back to the h-BN/Ni interface to form graphene. The resulting laterally continuous heterostructure is composed of a top layer of few-layer thick h-BN on an intermediate few-layer thick graphene, lying on top of Ni/MgO(111). Examinations by synchrotronbased grazing incidence diffraction, X-ray photoemission spectroscopy, and UV-Raman spectroscopy reveal that while the h-BN is relaxed, the lattice constant of graphene is significantly reduced, likely due to nitrogen doping. These results illustrate a different pathway for the production of h-BN/graphene heterostructures, and open a new perspective for the large-area preparation of heterosystems combining graphene and other 2D or 3D materials.

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  • 305.
    Wu, Zhengtao
    et al.
    Guangdong Univ Technol, Peoples R China.
    Tengstrand, Olof
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Bakhit, Babak
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Greene, Joseph E
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci and Technol, Taiwan.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Petrov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Univ Illinois, IL 61801 USA.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Growth of dense, hard yet low-stress Ti0.40Al0.27W0.33N nanocomposite films with rotating substrate and no external substrate heating2020In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 38, no 2Article in journal (Refereed)
    Abstract [en]

    W+ irradiation of TiAlN is used to demonstrate growth of dense, hard, and stress-free refractory nitride coatings with no external heating during reactive magnetron sputtering. Ti0.40Al0.27W0.33N nanocomposite films are deposited on Si(001) substrates using hybrid high-power impulse and dc magnetron cosputtering (HiPIMS and DCMS) in an industrial sputtering system employing substrate rotation during film growth from six cathodes. Two W targets powered by HiPIMS serve as a pulsed source of energetic W+ ions with incident fluxes analyzed by in situ time- and energy-resolved mass spectroscopy, while the remaining four targets (two elemental Ti targets and two Ti plates with Al plugs) are operated in the DCMS mode (W-HiPIMS/TiAl-DCMS) to provide a continuous flux of metal atoms and sustain a high deposition rate. A negative substrate bias V-s is applied only in synchronous with the W+-ion-rich portion of each HiPIMS pulse in order to provide film densification by heavy-ion irradiation of the TiAlN layers deposited between W+-ion exposures. W is selected for densification due to its high mass and relatively low reactivity with N-2, thus minimizing target poisoning while enhancing gas rarefaction. Dense Ti0.40Al0.27W0.33N alloy films, grown with no external substrate heating (substrate temperature T-s lower than 150 degrees C due to heat load from the plasma) and V-s=500V, exhibit a nanoindentation hardness of H=23.1GPa and an elastic modulus of E=378GPa, which are, respectively, 210% and 40% higher than for reference underdense DCMS Ti0.58Al0.42N films grown under the same conditions, but without W+ irradiation. The W ion bombardment does not affect the film stress state, which is compressive and low at 1.2GPa.

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  • 306.
    Xia, Yuxin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Polymer/polymer blends in organic photovoltaic and photodiode devices2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Organic photovoltaics devices (OPV) have attracted attentions of scientist for their potential as inexpensive, lightweight, flexible and suitable for roll-to-roll production. In recent years, considerable attention has been focused on new acceptor materials, either polymeric or small molecules, to replace the once dominating fullerene derivatives. The emergence of numerous new non-fullerene materials has driven power conversion efficiency (PCE) up to 17%, attracting more and more interests of commercialization.

    Polymer acceptors with more morphology stability, more absorption and more desired energy levels has been intensively studied and show great potential for large area and low-cost production in the future. OPV at this moment is not yet competitive with inorganic solar cells in PCE but is more attractive in flexibility, low weight and semitransparency. In this thesis, some basic knowledges of OPV is introduced in the first few chapters, while the next chapters are focusing on polymer-polymer blends and investigating novel structures and techniques for large scale production of solar cells and photodetectors aiming at maximizing these advantages to compete with inorganic counterpart.

    Thermal annealing effects on polymer-polymer solar cells based is studied. Annealed devices show doubled power conversion efficiency compared to non-annealed devices. Based on the morphology—mobility examination, we conclude that the better charge transport is achieved by higher order and better interconnected networks of the bulk heterojunction in the annealed active layers. The annealing improves charge transport and extends the conjugation length of the polymers, which do help charge generation and meanwhile reduce recombination. The blend of an amorphous polymer and a semi-crystalline polymer can thus be modified by thermal annealing to double the power conversion efficiency.

    A novel concept of all-polymer organic photovoltaics device is demonstrated in this thesis where all the layers are made out of polymers. We use PEDOT:PSS as semitransparent anode and polyethyleneimine modified PEDOT:PSS as semitransparent cathode, both of which are slot-die printed on polyethylene terephthalate(PET). Active layers are deposited on cathode and anode surfaces by spin coating separately. These layers are then joined through a roll-to-roll compatible lamination process. This forms a semitransparent and flexible solar cell. By laminating a thin layer acceptor polymer to a thick polymer-polymer blend, we can further improve the performance by reducing traps comparing to laminating blend to blend.

    Flexible and semitransparent all-polymer photodiodes with different geometries can be fabricated through lamination. By choosing high band gap polymers and appropriate combination of two or more polymers, organic photodiode with low noise and high specific detectivity can be obtained. Comparison between bilayer and bulk heterojunction devices gives better understanding of the origin of noise and provides ways to improve the performance of photodiodes as detector.

    Noise level is a critical parameter for photodetectors. The difficulties of measuring the noise of photodetectors make some researchers prefer the estimated shot noise as the dominating one and ignore the thermal noise and 1/f noise. The latter two terms are sometimes several orders higher than the former, noting the importance of experimentally measuring noise.

    The use of semi-transparent photovoltaic devices causes an inevitable loss of photocurrent, as light transmitted has not been absorbed. This trivial effect also leads to a loss of photovoltage, an effect partially due to the lower photocurrent but also due to the geometry of the semitransparent photovoltaic device. We here demonstrate and evaluate this photovoltage loss in semi-transparent organic photovoltaic devices, compared with non-transparent solar cells of the same material. Semi-transparent solar cells in addition introduce photovoltage loss when formed by lamination. We document and analyze these effects for a number of polymer blends in the form of bulk heterojunctions.

    List of papers
    1. Inverted all-polymer solar cells based on a quinoxaline-thiophene/naphthalene-diimide polymer blend improved by annealing
    Open this publication in new window or tab >>Inverted all-polymer solar cells based on a quinoxaline-thiophene/naphthalene-diimide polymer blend improved by annealing
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    2016 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 10, p. 3835-3843Article in journal (Refereed) Published
    Abstract [en]

    We have investigated the effect of thermal annealing on the photovoltaic parameters of all-polymer solar cells based on a quinoxaline-thiophene donor polymer (TQ1) and a naphthalene diimide acceptor polymer (N2200). The annealed devices show a doubled power conversion efficiency compared to nonannealed devices, due to the higher short-circuit current (J(sc)) and fill factor (FF), but with a lower open circuit voltage (V-oc). On the basis of the morphology-mobility examination by several scanning force microscopy techniques, and by grazing-incidence wide-angle X-ray scattering, we conclude that better charge transport is achieved by higher order and better interconnected networks of the bulk heterojunction in the annealed active layers. The annealing improves charge transport and extends the conjugation length of the polymers, which do help in charge generation and meanwhile reduce recombination. Photoluminescence, electroluminescence, and light intensity dependence measurements reveal how this morphological change affects charge generation and recombination. As a result, the J(sc) and FF are significantly improved. However, the smaller band gap and the higher HOMO level of TQ1 upon annealing causes a lower V-oc. The blend of an amorphous polymer TQ1, and a semi-crystalline polymer N2200, can thus be modified by thermal annealing to double the power conversion efficiency.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2016
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-127066 (URN)10.1039/c6ta00531d (DOI)000371967000030 ()
    Note

    Funding Agencies|Swedish Energy Agency; Swedish Research council, NSFC [21504006, 21534003]; Knut and Alice Wallenberg Foundation through a Wallenberg scholar grant; China Scholarship Council (CSC); graduate student short-term abroad research project of Jinan University; program for the Excellent Doctoral Dissertations of Guangdong Province [ybzzxm201114]; U.S. Department of Energy [DE-AC02-05CH11231]

    Available from: 2016-04-13 Created: 2016-04-13 Last updated: 2019-01-04
    2. Semitransparent all-polymer solar cells through lamination
    Open this publication in new window or tab >>Semitransparent all-polymer solar cells through lamination
    2018 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 42, p. 21186-21192Article in journal (Refereed) Published
    Abstract [en]

    In this work, we demonstrate all-polymer solar cells where all the layers are made from polymers. We use PEDOT:PSS as the semitransparent anode and polyethyleneimine modified PEDOT:PSS as the semitransparent cathode, both of which are slot-die printed on polyethylene terephthalate (PET). Active layers are deposited on the cathode and anode surfaces by spin coating separately. These layers are then joined through a roll-to-roll compatible lamination process. This results in a semitransparent and flexible solar cell. We have used two polymer-polymer systems and several combinations, and the highest power conversion efficiency (PCE) obtained is 2.3% with a mean transparency amp;gt;35% within the visible light range. By laminating a thin layer acceptor polymer to a thick polymer-polymer blend, we can improve the performance by reducing recombination, compared to laminating blend to blend, which is verified by the trap-limited charge transport, CELIV and electroluminescence.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2018
    National Category
    Polymer Chemistry
    Identifiers
    urn:nbn:se:liu:diva-153535 (URN)10.1039/c8ta07992g (DOI)000451600200066 ()
    Note

    Funding Agencies|Swedish Energy Agency; Knut and Alice Wallenberg foundation (KAW); China Scholarship Council (CSC)

    Available from: 2018-12-20 Created: 2018-12-20 Last updated: 2019-03-25
    3. Large-Area, Semitransparent, and Flexible All-Polymer Photodetectors
    Open this publication in new window or tab >>Large-Area, Semitransparent, and Flexible All-Polymer Photodetectors
    Show others...
    2018 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, no 48, article id 1805570Article in journal (Refereed) Published
    Abstract [en]

    Photodetectors, converting optical signals from specific wavelengths to electrical signals, have many applications on photoimaging, optical communication, and environmental monitoring. Solution-processed organic photodetectors (OPDs) based on organic materials emerge promise especially for wearable electronics and smart buildings. In this work, new all-polymer photodetectors (all-PPDs) are developed based on bulk-heterojunction active layers which incorporate a donor polymer and an acceptor polymer. The inverted all-PPDs exhibit outstanding external quantum efficiency over 70%, low dark current density (J(d)) of 1.1 x 10(-8) A cm(-2), and high detectivity (D*) over 3.0 x 10(12) Jones with planar response over the entire visible range. It is one of the best-performing all-PPDs reported so far and is also comparable with many organic and inorganic photodetectors. By using lamination technique, large-area, semitransparent, flexible, and "fully" polymeric photodetectors are successfully fabricated for the first time, with D* over 10(11) Jones for double-side light detection. The results highlight the great potential for producing high-performance all-PPDs by taking advantages of various device architecture and solution-processing techniques.

    Place, publisher, year, edition, pages
    WILEY-V C H VERLAG GMBH, 2018
    Keywords
    all-polymer photodetectors; conjugated polymers; flexible electronics; semitransparent electronics
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-153367 (URN)10.1002/adfm.201805570 (DOI)000451118800014 ()
    Note

    Funding Agencies|Knut and Alice Wallenberg foundation through a Wallenberg Scholar grant; Ocean University of China; Ministry of Science and Technology [2016YFA0200700]; National Natural Science Foundation of China [21704082, 21875182, 21534003, 51320105014]; China Postdoctoral Science Foundation [2017M623162]; Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy [DE-AC02-05CH11231]; China Scholarship Council (CSC)

    Available from: 2018-12-18 Created: 2018-12-18 Last updated: 2019-01-04
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    Polymer/polymer blends in organic photovoltaic and photodiode devices
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  • 307.
    Xing, Xing
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Chuan Fei
    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.
    Leiqiang, Qin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Ergang
    Chalmers University of Technology, Sweden.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    The trade-off between electrochromic stability and contrast of a thiophene-Quinoxaline copolymer2017In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 253, p. 530-535Article in journal (Refereed)
    Abstract [en]

    The stability of organic electrochromic devices is a crucial issue for their applications. However, until now the degradation mechanism of electrochromic materials are still not fully understood especially for electrochromic conjugated polymers (ECPs). To improve device stability, intensive investigation on the degradation mechanism of ECPs is urgently needed. Here we report our study on the electrochromic degradation in a thiophene-quinoxaline copolymer: poly [2,3-bis-(3-octyloxyphenyl) quinoxaline-5,8diyl- alt-thiophene-2,5-diyl] (TQ1). The results of X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectra (UPS) and UV-vis transmission spectra reveal that there are three main factors during the electrochromic degradation of TQ1. The first one is anion (ClO4-) irreversibly deep trapped, while the second is peroxidation of the thiophene group in TQ1. Both factors reduce the conductivity and electrochromism of TQ1. The third is structural relaxation resulting lager conjugated system of TQ1 molecules in film, which is gradually developed during 400 cycling of CV at a narrow potential range (01 V). When a potential range 0-0.7 V is applied, all three factors are prohibited, no electrochromism degradation is observed anymore, although the contrast becomes smaller. Our investigation systematically discloses the degradation mechanism during the electrochemistry processing of a ECP (TQ1), demonstrating the significance of trade-off between the electrochromic stability and contrast of the ECP. (C) 2017 Elsevier Ltd. All rights reserved.

  • 308.
    Xing, Xing
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zeng, Qi
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Physics and Electronics. 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.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Fast switching polymeric electrochromics with facile processed water dispersed nanoparticles2018In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 47, p. 123-129Article in journal (Refereed)
    Abstract [en]

    In this work, water dispersed electrochromic polymer nanoparticles (WDENs) prepared with miniemulsion process are introduced into electrochromic polymer (ECP) electrode for the first time. The poly [2, 3-bis-(3-octyloxyphenyl) quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl]) nanoparticle (NP) electrode shows much faster switching speed than the compacted electrode (e.g. 2.10 s vs. 24.15 s for coloring, 8.65 s vs. 25.95 s for bleaching @ 0.4 V; 1.30 s vs. 9.20 s coloring and 1.7 s vs. 2.90 s for bleaching @ 1.0 V). Moreover, the potentiality of WDENs for universal ECPs is demonstrated. The microelectrochemical measurement indicates much more efficient counter-ion diffusion between the electrolyte and the NP films than the compacted films, which results in much faster electrochromic switching. Besides the facile and eco-friendly processing of the WDENs, all solution and low cost fabrication of ECP NP films suggest their broad applications in commercial production of polymer electrochromic display and great potential for other polymer electrochemical electronics.

  • 309.
    Xiong, Shaobing
    et al.
    East China Normal Univ, Peoples R China.
    Song, Jingnan
    Shanghai Jiao Tong Univ, Peoples R China.
    Yang, Jianming
    East China Normal Univ, Peoples R China.
    Xu, Jinqiu
    Shanghai Jiao Tong Univ, Peoples R China.
    Zhang, Ming
    Shanghai Jiao Tong Univ, Peoples R China.
    Ma, Ruru
    East China Normal Univ, Peoples R China.
    Li, Danqin
    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.
    Liu, Feng
    Shanghai Jiao Tong Univ, Peoples R China.
    Duan, Chungang
    East China Normal Univ, Peoples R China; Shanxi Univ, Peoples R China.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Bao, Qinye
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. East China Normal Univ, Peoples R China; Shanxi Univ, Peoples R China.
    Defect-Passivation Using Organic Dyes for Enhanced Efficiency and Stability of Perovskite Solar Cells2020In: SOLAR RRL, ISSN 2367-198X, article id 1900529Article in journal (Refereed)
    Abstract [en]

    Perovskite solar cells are a highly competitive candidate for next-generation photovoltaic technology. Defects in the perovskite grain boundaries and on the film surfaces however have significant impacts on both the device efficiency and environmental stability. Herein, a strategy using organic dyes as additives to passivate the defect states and produce more n-type perovskite films, thereby improving charge transport and decreasing charge recombination, is reported. Based on this strategy, the power conversion efficiency of the perovskite solar cell is significantly increased from 18.13% to 20.18% with a negligible hysteresis. Furthermore, the rich hydrogen bonds and carbonyl structures in the organic dye can significantly enhance device stability both in terms of humidity and thermal stress. The results present a promising pathway using abundant and colorful organic dyes as additives to achieve high-performance perovskite solar cells.

  • 310.
    Xiong, Sixing
    et al.
    Huazhong Univ Sci and Technol, Peoples R China.
    Hu, Lin
    Huazhong Univ Sci and Technol, Peoples R China.
    Hu, Lu
    Huazhong Univ Sci and Technol, Peoples R China.
    Sun, Lulu
    Huazhong Univ Sci and Technol, Peoples R China.
    Qin, Fei
    Huazhong Univ Sci and Technol, Peoples R China.
    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 Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhou, Yinhua
    Huazhong Univ Sci and Technol, Peoples R China.
    12.5% Flexible Nonfullerene Solar Cells by Passivating the Chemical Interaction Between the Active Layer and Polymer Interfacial Layer2019In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 31, no 22, article id 1806616Article in journal (Refereed)
    Abstract [en]

    Nonfullerene (NF) organic solar cells (OSCs) have been attracting significant attention in the past several years. It is still challenging to achieve high-performance flexible NF OSCs. NF acceptors are chemically reactive and tend to react with the low-temperature-processed low-work-function (low-WF) interfacial layers, such as polyethylenimine ethoxylated (PEIE), which leads to the S shape in the current-density characteristics of the cells. In this work, the chemical interaction between the NF active layer and the polymer interfacial layer of PEIE is deactivated by increasing its protonation. The PEIE processed from aqueous solution shows more protonated N+ than that processed from isopropyl alcohol solution, observed from X-ray photoelectron spectroscopy. NF solar cells (active layer: PCE-10:IEICO-4F) with the protonated PEIE interfacial layer show an efficiency of 13.2%, which is higher than the reference cells with a ZnO interlayer (12.6%). More importantly, the protonated PEIE interfacial layer processed from aqueous solution does not require a further thermal annealing treatment (only processing at room temperature). The room-temperature processing and effective WF reduction enable the demonstration of high-performance (12.5%) flexible NF OSCs.

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  • 311.
    Xu, Xiaofeng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. Ocean Univ China, Peoples R China.
    Zhou, Xiaobo
    Xi An Jiao Tong Univ, Peoples R China.
    Zhou, Ke
    Xi An Jiao Tong Univ, Peoples R China.
    Xia, Yuxin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ma, Wei
    Xi An Jiao Tong Univ, Peoples R China.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Large-Area, Semitransparent, and Flexible All-Polymer Photodetectors2018In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, no 48, article id 1805570Article in journal (Refereed)
    Abstract [en]

    Photodetectors, converting optical signals from specific wavelengths to electrical signals, have many applications on photoimaging, optical communication, and environmental monitoring. Solution-processed organic photodetectors (OPDs) based on organic materials emerge promise especially for wearable electronics and smart buildings. In this work, new all-polymer photodetectors (all-PPDs) are developed based on bulk-heterojunction active layers which incorporate a donor polymer and an acceptor polymer. The inverted all-PPDs exhibit outstanding external quantum efficiency over 70%, low dark current density (J(d)) of 1.1 x 10(-8) A cm(-2), and high detectivity (D*) over 3.0 x 10(12) Jones with planar response over the entire visible range. It is one of the best-performing all-PPDs reported so far and is also comparable with many organic and inorganic photodetectors. By using lamination technique, large-area, semitransparent, flexible, and "fully" polymeric photodetectors are successfully fabricated for the first time, with D* over 10(11) Jones for double-side light detection. The results highlight the great potential for producing high-performance all-PPDs by taking advantages of various device architecture and solution-processing techniques.

  • 312.
    Yang, Jianming
    et al.
    East China Normal Univ, Peoples R China.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Zhang, Yuexing
    Soochow Univ, Peoples R China.
    Zheng, Xuerong
    Zhejiang Univ, Peoples R China.
    He, Xiaoxiao
    East China Normal Univ, Peoples R China.
    Wang, Han
    East China Normal Univ, Peoples R China.
    Yue, Fangyu
    East China Normal Univ, Peoples R China.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Chen, Jinquan
    East China Normal Univ, Peoples R China.
    Xu, Jianhua
    East China Normal Univ, Peoples R China.
    Li, Yanqing
    Soochow Univ, Peoples R China.
    Jin, Yizheng
    Zhejiang Univ, Peoples R China.
    Tang, Jianxin
    Soochow Univ, Peoples R China.
    Duan, Chungang
    East China Normal Univ, Peoples R China; Shanxi Univ, Peoples R China.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Bao, Qinye
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering. East China Normal Univ, Peoples R China; Shanxi Univ, Peoples R China.
    Comprehensive understanding of heat-induced degradation of triple-cation mixed halide perovskite for a robust solar cell2018In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 54, p. 218-226Article in journal (Refereed)
    Abstract [en]

    The triple-cation mixed halide perovskite Cs-0.05(MA(0.17)FA(0.83))(0.95)Pb(I0.83Br0.17)(3) emerges as one of the most promising candidates for photovoltaics due to superior optoelectronic properties, but the thermal stability is still a major challenge for the viability of perovskite solar cells towards commercialization. Herein, we firstly explore the thermal response of the photovoltaic performances to access device physical changes. It is shown that the efficiency loss originates from decreased charge mobility, increased trap density and generation of PbI2 charge recombination centers near the interface. In-depth analysis of evolutions in morphology, chemical composition, dynamic and electronic structure of the perovskite layer at the nanometer scales indicates that it is initial dangling bonds and vacancies on the imperfect surfaces decrease the activation energy and cause the perovskite decomposition in a layer-by-layer pathway sequentially from the film surface to bulk. Based on the results, a strategy of surface passivation to improve the thermal stability is demonstrated and discussed. This work for the first time provides insights into the physical and chemical change of such triple-cation perovskite and indicates that more effort should be invested in surface treatment for enhancing perovskite device stability.

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  • 313.
    Yang, Jianming
    et al.
    East China Normal Univ, Peoples R China.
    Xiong, Shaobing
    East China Normal Univ, Peoples R China.
    Qu, Tianyi
    Soochow Univ, Peoples R China.
    Zhang, Yuexing
    Soochow Univ, Peoples R China.
    He, Xiaoxiao
    East China Normal Univ, Peoples R China.
    Guo, Xuewen
    East China Normal Univ, Peoples R China.
    Zhao, Qiuhua
    East China Normal Univ, Peoples R China.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Chen, Jinquan
    East China Normal Univ, Peoples R China.
    Xu, Jianhua
    East China Normal Univ, Peoples R China.
    L, Yanqing I
    Soochow Univ, Peoples R China.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Duan, Chungang
    East China Normal Univ, Peoples R China; Shanxi Univ, Peoples R China.
    Tang, Jianxin
    Soochow Univ, Peoples R China.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Bao, Qinye
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering. East China Normal Univ, Peoples R China; Shanxi Univ, Peoples R China.
    Extremely Low-Cost and Green Cellulose Passivating Perovskites for Stable and High-Performance Solar Cells2019In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 14, p. 13491-13498Article in journal (Refereed)
    Abstract [en]

    The fast evolution of metal halide perovskite solar cells has opened a new chapter in the field of renewable energy. High-quality perovskite films as the active layers are essential for both high efficiency and long-term stability. Here, the perovskite films with enlarged crystal grain size and decreased defect density are fabricated by introducing the extremely low-cost and green polymer, ethyl cellulose (EC), into the perovskite layer. The addition of EC triggers hydrogen bonding interactions between EC and the perovskite, passivating the charge defect traps at the grain boundaries. The long chain of EC further acts as a scaffold for the perovskite structure, eliminating the annealing-induced lattice strain during the film fabrication process. The resulting devices with the EC additive exhibit a remarkably enhanced average power conversion efficiency from 17.11 to 19.27% and an improvement of all device parameters. The hysteresis index is found to decrease by three times from 0.081 to 0.027, which is attributed to suppressed ion migration and surface charge trapping. In addition, the defect passivation by EC significantly improves the environmental stability of the perovskite films, yielding devices that retain 80% of their initial efficiency after 30 days in ambient air at 45% relative humidity, whereas the pristine devices without EC fully degrade. This work provides a low-cost and green avenue for passivating defects that improves both the efficiency and operational stability of perovskite solar cells.

  • 314.
    Yang, Junyu
    et al.
    Jinan Univ, Peoples R China.
    Lin, Yuanbao
    Jinan Univ, Peoples R China.
    Zheng, Wenhao
    Jinan Univ, Peoples R China.
    Liu, Alei
    Jinan Univ, Peoples R China.
    Cai, Wanzhu
    Jinan Univ, Peoples R China.
    Yu, Xiaomin
    Jinan Univ, Peoples R China.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. Jinan Univ, Peoples R China.
    Liang, Quanbin
    South China Univ Technol, Peoples R China.
    Wu, Hongbin
    South China Univ Technol, Peoples R China.
    Qin, Donghuan
    South China Univ Technol, Peoples R China.
    Hou, Lintao
    Jinan Univ, Peoples R China.
    Roll-to-Roll Slot-Die-Printed Polymer Solar Cells by Self-Assembly2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 26, p. 22485-22494Article in journal (Refereed)
    Abstract [en]

    Extremely simplified one-step roll-to-roll slot-die-printed flexible indium tin oxide (ITO)-free polymer solar cells (PSCs) are demonstrated based on the ternary blends of electron-donor polymer thieno[3,4-b]thiophene/benzodithiophene, electron-acceptor fullerene [6,6]-phenyl-C-71-butyric acid methyl ester, and electron-extracting polymer poly[(9,9-bis(3-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) at room temperature (RT) in ambient air. The flexible ITO-free PSC exhibits a comparable power conversion efficiency (PCE) with the device employing complicated two-step slot-die printing (5.29% vs 5.41%), which indicates that PFN molecules can migrate from the ternary nanocomposite toward the Ag cathode via vertical self-assembly during the one-step slot-die printing process in air. To confirm the migration of PFN, the morphology and elemental analysis as well as charge transport of different active layers are investigated by the in situ transient film drying process, transmission electron microscopy, atomic force microscopy, contact angle and surface energy, X-ray photoelectron spectroscopy, scanning electron microscopy, impedance spectroscopy, transient photovoltage and transient photocurrent, and laser-beam-induced current. Moreover, the good air and mechanical stability of the flexible device with a decent PCE achieved in 1 cm(2) PSCs at RT in air suggests the feasibility of energy-saving and time-saving one-step slot-die printing to large-scale roll-to-roll manufacture in the future.

  • 315.
    Yang, Rong
    et al.
    Nanjing Technical University, Peoples R China.
    Zhang, Li
    Nanjing Technical University, Peoples R China.
    Cao, Yu
    Nanjing Technical University, Peoples R China.
    Miao, Yanfeng
    Nanjing Technical University, Peoples R China.
    Ke, You
    Nanjing Technical University, Peoples R China.
    Wei, Yingqiang
    Nanjing Technical University, Peoples R China.
    Guo, Qiang
    Nanjing Technical University, Peoples R China.
    Wang, Ying
    Nanjing Technical University, Peoples R China.
    Rong, Zhaohua
    Nanjing Technical University, Peoples R China.
    Wang, Nana
    Nanjing Technical University, Peoples R China.
    Li, Renzhi
    Nanjing Technical University, Peoples R China.
    Wang, Jianpu
    Nanjing Technical University, Peoples R China.
    Huang, Wei
    Nanjing Technical University, Peoples R China; Nanjing University of Posts and Telecommun, Peoples R China; Nanjing University of Posts and Telecommun, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inhomogeneous degradation in metal halide perovskites2017In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 111, no 7, article id 073302Article in journal (Refereed)
    Abstract [en]

    Although the rapid development of organic-inorganic metal halide perovskite solar cells has led to certified power conversion efficiencies of above 20%, their poor stability remains a major challenge, preventing their practical commercialization. In this paper, we investigate the intrinsic origin of the poor stability in perovskite solar cells by using a confocal fluorescence microscope. We find that the degradation of perovskite films starts from grain boundaries and gradually extend to the center of the grains. Firmly based on our findings, we further demonstrate that the device stability can be significantly enhanced by increasing the grain size of perovskite crystals. Our results have important implications to further enhance the stability of optoelectronic devices based on metal halide perovskites. Published by AIP Publishing.

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  • 316.
    Yasin, M. Naveed
    et al.
    Univ Auckland, New Zealand; Univ Auckland, New Zealand; Fac Engn, Canada.
    Brooke, Robert
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. Univ South Australia, Australia.
    Rudd, Sam
    Univ South Australia, Australia.
    Chan, Andrew
    Univ Auckland, New Zealand.
    Chen, Wan-Ting
    Univ Auckland, New Zealand.
    Waterhouse, Geoffrey I. N.
    Univ Auckland, New Zealand; Univ Auckland, New Zealand.
    Evans, Drew
    Univ South Australia, Australia.
    Rupenthal, Ilva D.
    Univ Auckland, New Zealand.
    Svirskis, Darren
    Univ Auckland, New Zealand.
    3-Dimensionally ordered macroporous PEDOT ion-exchange resins prepared by vapor phase polymerization for triggered drug delivery: Fabrication and characterization2018In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 269, p. 560-570Article in journal (Refereed)
    Abstract [en]

    This paper reports a simple fabrication strategy towards 3-dimensionally ordered macroporous (3DOM) poly(3,4-ethylenedioxythiophene) (PEDOT) thin films via vapor phase polymerization (VPP) coupled with colloidal crystal templating. PEDOT was synthesized by VPP over a colloidal crystal thin film composed of monodisperse polystyrene colloids functionalized with a Fe(III) tosylate catalyst, after which the polystyrene template was selectively removed. The resulting 3DOM PEDOT films comprised a face-centered cubic array of 280-290 nm spherical macropores in a PEDOT matrix, around 5-6 mu m thick. Cyclic voltammetry (CV) was used to probe electrochemistry and highlighted the merits of the fabrication strategy introduced here; the 3DOM PEDOT films exhibit a 2.9-fold increase in electrochemically available surface area compared to the non-templated PEDOT films. As a demonstration of functionality, ion-exchange of the dopant tosylate for the anionic drug dexamethasone phosphate (dexP(-)) was explored. Loading by passive ion exchange was three-fold higher for 3DOM PEDOT compared with non-templated PEDOT. Notably, CV-driven ion exchange was more efficient to load drug into the polymer than passive ion exchange, and occurred to similar extents for both non-templated PEDOT and 3DOM PEDOT structures. Following loading, minimal dexP(-) release was observed in the absence of an electrical stimulus, while dexP(-) release was triggered upon application of a suitable electrical stimulus. 3DOM PEDOT prepared by VPP thus represents a promising material for use as an ion exchange resin with drug loading achieved subsequent to polymerization and electrically triggered drug release demonstrated. (c) 2018 Elsevier Ltd. All rights reserved.

  • 317.
    Yazdi, Gholamreza
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Akhtar, Fatima
    IHP, Germany.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Schmidt, Susann
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Shtepliuk, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Zakharov, Alexei
    Lund Univ, Sweden.
    Iakimov, Tihomir
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Effect of epitaxial graphene morphology on adsorption of ambient species2019In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 486, p. 239-248Article in journal (Refereed)
    Abstract [en]

    This work illustrates the impact of atmospheric gases on the surface of epitaxial graphene. The different rate of adsorption on different parts of graphene samples provides a concrete evidence that the surface morphology of graphene plays a significant role in this process. The uneven adsorption occurs only on the surface of the monolayer graphene and not on bilayer graphene. The second monolayer is distinguished and verified by the phase contrast mode of atomic force microscopy and the low energy electron microscopy, respectively. Raman spectroscopy is used to study the strain on the surface of graphene; results indicate that monolayer and bilayer graphene exhibit different types of strain. The bilayer is under more compressive strain in comparison with monolayer graphene that hinders the process of adsorption. However, the wrinkles and edges of steps of the bilayer are under tensile strain, hence, facilitate adsorption. Samples were subjected to X-ray photoelectron spectroscopy which confirms that the adsorbates on the epitaxial graphene are carbon clusters with nitrogen and oxygen contamination. For reversing the adsorption process the samples are annealed and a method for the removal of these adsorbates is proposed.

  • 318.
    Yu, Byoung-Soo
    et al.
    Kwangwoon University, South Korea.
    Jeon, Jun-Young
    Kwangwoon University, South Korea.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Ha, Tae-Jun
    Kwangwoon University, South Korea.
    Characteristics of Low-Temperature Solution-Processed Boron Nitride Thin Films for Flexible Nanoelectronics2017In: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 17, no 11, p. 8567-8570Article in journal (Refereed)
    Abstract [en]

    In this study, we demonstrate the characteristics of high quality boron nitride (BN) thin films for high performance 2 dimensional nanoelectronics. Such thin films were deposited using solution-process technology such as spin-coating, spraying and aerosol deposition at low temperature of 100 degrees C. The material properties of these BN thin films with optimized fabrication processes are competitive with those of BN deposited by employing the vacuum chemical vapor deposition technique. In order to characterize the material properties of solution-processed BN thin films, various measurements including atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were performed. The optimized solution-process based on BN thin films are practical and reproducible in achieving high performance flexible nanoelectronics which require low process temperature and good uniformity in large-area.

  • 319.
    Yu, Liyang
    et al.
    Sichuan Univ, Peoples R China; Chalmers Univ Technol, Sweden.
    Qian, Deping
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Marina, Sara
    Univ Basque Country, Spain; Univ Basque Country, Spain.
    Nugroho, Ferry A. A.
    Chalmers Univ Technol, Sweden.
    Sharma, Anirudh
    Flinders Univ S Australia, Australia; Univ Bordeaux, France.
    Hultmark, Sandra
    Chalmers Univ Technol, Sweden.
    Hofmann, Anna I.
    Chalmers Univ Technol, Sweden.
    Kroon, Renee
    Chalmers Univ Technol, Sweden.
    Benduhn, Johannes
    Tech Univ Dresden, Germany; Tech Univ Dresden, Germany.
    Smilgies, Detlef-M.
    CHESS, NY 14850 USA.
    Vandewal, Koen
    Hasselt Univ, Belgium.
    Andersson, Mats R.
    Flinders Univ S Australia, Australia.
    Langhammer, Christoph
    Chalmers Univ Technol, Sweden.
    Martin, Jaime
    Univ Basque Country, Spain; Univ Basque Country, Spain; Ikerbasque, Spain.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Mueller, Christian
    Chalmers Univ Technol, Sweden.
    Diffusion-Limited Crystallization: A Rationale for the Thermal Stability of Non-Fullerene Solar Cells2019In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 24, p. 21766-21774Article in journal (Refereed)
    Abstract [en]

    Organic solar cells are thought to suffer from poor thermal stability of the active layer nanostructure, a common belief that is based on the extensive work that has been carried out on fullerene-based systems. We show that a widely studied non-fullerene acceptor, the indacenodithienothiophene-based acceptor ITIC, crystallizes in a profoundly different way as compared to fullerenes. Although fullerenes are frozen below the glass-transition temperature T-g of the photovoltaic blend, ITIC can undergo a glass-crystal transition considerably below its high T-g of similar to 180 degrees C. Nanoscopic crystallites of a low-temperature polymorph are able to form through a diffusion-limited crystallization process. The resulting fine-grained nanostructure does not evolve further with time and hence is characterized by a high degree of thermal stability. Instead, above T-g, the low temperature polymorph melts, and micrometer-sized crystals of a high-temperature polymorph develop, enabled by more rapid diffusion and hence long-range mass transport. This leads to the same detrimental decrease in photovoltaic performance that is known to occur also in the case of fullerene-based blends. Besides explaining the superior thermal stability of non-fullerene blends at relatively high temperatures, our work introduces a new rationale for the design of bulk heterojunctions that is not based on the selection of high-T-g materials per se but diffusion-limited crystallization. The planar structure of ITIC and potentially other non-fullerene acceptors readily facilitates the desired glass-crystal transition, which constitutes a significant advantage over fullerenes, and may pave the way for truly stable organic solar cells.

  • 320.
    Yuan, Jianyu
    et al.
    Soochow University, Peoples R China.
    Guo, Wenping
    Fudan University, Peoples R China.
    Xia, Yuxin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ford, Michael J.
    University of Calif Santa Barbara, CA 93106 USA; University of Calif Santa Barbara, CA 93106 USA.
    Jin, Feng
    Fudan University, Peoples R China.
    Liu, Dongyang
    Soochow University, Peoples R China.
    Zhao, Haibin
    Fudan University, Peoples R China.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Bazan, Guillermo C.
    University of Calif Santa Barbara, CA 93106 USA; University of Calif Santa Barbara, CA 93106 USA.
    Ma, Wanli
    Soochow University, Peoples R China.
    Comparing the device physics, dynamics and morphology of polymer solar cells employing conventional PCBM and non-fullerene polymer acceptor N22002017In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 35, p. 251-262Article in journal (Refereed)
    Abstract [en]

    Current all polymer solar cells still suffer from low fill factors (FF) and short-circuit current density (J(sc)) compared with the conventional polymer/fullerene system. Herein in this work, devices using PTP8 as the electron donor and [70]PCBM as well as widely used polymer N2200 as the electron acceptor were systematically studied and compared. The major loss mechanisms in the all polymer solar cells were investigated to understand their relatively lower performance than the PTP8/fullerene system. By performing in-depth analysis on ultrafast transient transmission spectroscopy results, we estimated that in PTP8/N2200 device nearly half of the charges recombine geminately, which is confirmed as the major factor hindering the device performance of all polymer solar cells compared with polymer/fullerene system. Through thorough morphology analysis, the low charge generation efficiency is attributed to the reduced crystallinity of N2200 in the blend film and the unfavorable face-to-edge orientation at the donor/acceptor heterojunction. Coupling these results with knowledge from efficient polymer/fullerene systems, the future design of new polymers can devote to increase the attraction between the pi face of donor and acceptor, leading to enhanced face-to-face orientation at the heterojunction, while maintaining a high pi-pi stacking order for each polymer.

  • 321.
    Yuan, Kang
    et al.
    Beijing General Research Institute of Mining and Metallurgy, Beijing, China.
    Jonnalagadda, Krisha Praveen
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Yu, Yueguang
    Beijing General Research Institute of Mining and Metallurgy, Beijing, China.
    Peng, Ru Lin
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Li, Xin-Hai
    Department of Management and Engineering, Linköping University, S.
    Ji, Xiaojuan
    Beijing General Research Institute of Mining and Metallurgy, Beijing, China.
    Shen, Jie
    Beijing General Research Institute of Mining and Metallurgy, Beijing, China.
    Thermal fatigue failure of thermal barrier coatings with a high-Cr MCrAIY bond coat2016In: Proceedings of the International Thermal Spray Conference (ITSC), 2016, Vol. 324, p. 273-278Conference paper (Refereed)
    Abstract [en]

    Thermal barrier coatings (TBCs) were air-plasma sprayed onto Hastelloy X substrates. The TBCs consisted of a high-Cr MCrAlY (M for Ni and Co) bond coat and a yttria-stabilized zirconia (YSZ) top coat. The TBC samples were thermally cycled between 100 ºC and 1100 ºC with 1 hour dwell time at 1100 ºC. The thermal fatigue failure of the TBCs was investigated via microstructure analyses. The final fatigue failure of the TBCs was caused by the formation of interface-parallel cracks in the YSZ top coat. The formation of the cracks was found to be strongly related to the oxidation behaviour of the MCrAlY bond coat. The development of the oxide layers was therefore studied in detail. A thermokinetic model was also used to deepen the understanding on the elemental diffusion behavior in the materials.

  • 322. Order onlineBuy this publication >>
    Yuan, Zhongcheng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Defects and crystallinity control of perovskite films for light-emitting diodes2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Metal halide perovskites are promising materials for the fabrication of cost-effective and highperformance light-emitting diodes (LEDs), due to their solution processability, high photoluminescence quantum efficiencies (PLQEs) and excellent charge transport properties. Importantly, perovskite LEDs show ultra-pure emission color, which is better than that of the state-of-the-art quantum dot LEDs (QLEDs) and organic LEDs (OLEDs), demonstrating a bright application potential for realizing vivid natural colors display in the future.

    In this thesis, we first incorporate natural molecules, e.g. deoxyribonucleic acid (DNA), to passivate FAPbI3 perovskite films. We notice that the existence of carbonyl and amide groups within DNA are important for efficient passivation of perovskite films. Combining the knowledge, we further introduce amino-functionalized molecules into perovskite films and achieve significantly improved efficiency of 21.6 %, which is a record external quantum efficiency (EQE) of perovskite LEDs. We reveal that by weakening the hydrogen bond strength between passivation molecules and organic cations, the interaction between passivation amino groups and defects improves, contributing to more efficient passivation.

    We also notice that the underlying substrates play important roles on the film quality of perovskite and the device performance of the ensuing LEDs. Here, we reveal that efficient deprotonation of the undesirable organic cations (Methylammonium (MA+) or Formamidinium (FA+)) by a metal oxide interlayer, e.g. ZnO, with a high isoelectric point, is critical to promote the transition from intermediate phases to highly emissive perovskites. We reveal synergistic effects of precursor stoichiometry and interfacial reactions for high-performance perovskite LEDs, and establish useful guidelines for rational device optimisation. With the knowledge we obtain from the deprotonation process, we further push the EL emission from near-infrared (NIR) (around 800 nm) region to deep red emission (around 700 nm) via cation exchange process between cesium (Cs+) and FA+, which promotes enhanced crystallization of the perovskite films and devices performance simultaneously.

    Intensive efforts in the perovskite community have pushed the EQEs of perovskite LEDs to over 20 %for green, red and NIR emission region. However, it is still a long way to go before their practical applications. We believe that efficient control of both the defects and crystallinity of the perovskite films through rational materials development and interfacial modifications is important for the development of perovskite optoelectronic devices. In addition, both our findings on the perovskite film quality control are universal and provide insights to promote the development of perovskites (especially the hybrid ones containing organic components) for the applications of other optoelectronic devices.

    List of papers
    1. Rational molecular passivation for high-performance perovskite light-emitting diodes
    Open this publication in new window or tab >>Rational molecular passivation for high-performance perovskite light-emitting diodes
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    2019 (English)In: Nature Photonics, ISSN 1749-4885, E-ISSN 1749-4893, Vol. 13, no 6, p. 418-424Article in journal (Refereed) Published
    Abstract [en]

    A major efficiency limit for solution-processed perovskite optoelectronic devices, for example light-emitting diodes, is trap-mediated non-radiative losses. Defect passivation using organic molecules has been identified as an attractive approach to tackle this issue. However, implementation of this approach has been hindered by a lack of deep understanding of how the molecular structures influence the effectiveness of passivation. We show that the so far largely ignored hydrogen bonds play a critical role in affecting the passivation. By weakening the hydrogen bonding between the passivating functional moieties and the organic cation featuring in the perovskite, we significantly enhance the interaction with defect sites and minimize non-radiative recombination losses. Consequently, we achieve exceptionally high-performance near-infrared perovskite light-emitting diodes with a record external quantum efficiency of 21.6%. In addition, our passivated perovskite light-emitting diodes maintain a high external quantum efficiency of 20.1% and a wall-plug efficiency of 11.0% at a high current density of 200 mA cm−2, making them more attractive than the most efficient organic and quantum-dot light-emitting diodes at high excitations.

    Place, publisher, year, edition, pages
    Springer Nature Publishing AG, 2019
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-157707 (URN)10.1038/s41566-019-0390-x (DOI)000468752300019 ()
    Note

    Funding agencies:  ERC Starting Grant [717026]; National Basic Research Program of China (973 Program) [2015CB932200]; National Natural Science Foundation of China [61704077, 51572016, 51721001, 61634001, 61725502, 91733302, U1530401]; Natural Science Foundation of Jiangsu 

    Available from: 2019-06-19 Created: 2019-06-19 Last updated: 2019-10-10Bibliographically approved
    2. Room-temperature film formation of metal halide perovskites on n-type metal oxides: the catalysis of ZnO on perovskite crystallization
    Open this publication in new window or tab >>Room-temperature film formation of metal halide perovskites on n-type metal oxides: the catalysis of ZnO on perovskite crystallization
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    2018 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, no 50, p. 6887-6890Article in journal (Refereed) Published
    Abstract [en]

    We investigate the effect of commonly used solution-processed TiOx, SnO2 and ZnO interlayers on the perovskite film crystallization process. We find that the ZnO/perovskite interface can efficiently catalyze the perovskite crystallization even without thermal annealing.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2018
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-149712 (URN)10.1039/c8cc02482k (DOI)000436029000052 ()29781476 (PubMedID)
    Note

    Funding Agencies|ERC [717026]; Carl Tryggers Stiftelse; European Commission [691210]; China Scholarship Council; VINNMER Marie Curie Fellowships

    Available from: 2018-07-24 Created: 2018-07-24 Last updated: 2019-06-19
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    Defects and crystallinity control of perovskite films for light-emitting diodes
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  • 323.
    Yuan, Zhongcheng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Soochow University, Peoples R China.
    Yang, Yingguo
    Chinese Academic Science, Peoples R China.
    Wu, Zhongwei
    Soochow University, Peoples R China.
    Bai, Sai
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Xu, Weidong
    Soochow University, Peoples R China.
    Song, Tao
    Soochow University, Peoples R China.
    Gao, Xingyu
    Chinese Academic Science, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sun, Baoquan
    Soochow University, Peoples R China.
    Approximately 800-nm-Thick Pinhole-Free Perovskite Films via Facile Solvent Retarding Process for Efficient Planar Solar Cells2016In: ACS APPLIED MATERIALS and INTERFACES, ISSN 1944-8244, Vol. 8, no 50, p. 34446-34454Article in journal (Refereed)
    Abstract [en]

    Device performance of organometal halide perovskite solar cells significantly depends on the quality and thickness of perovskite absorber films. However, conventional deposition methods often generate pinholes within similar to 300 nm-thick perovskite films, which are detrimental to the large area device manufacture. Here we demonstrated a simple solvent retarding process to deposit uniform pinhole free perovskite films with thicknesses up to similar to 800 nm. Solvent evaporation during the retarding process facilitated the components separation in the mixed halide perovskite precursors, and hence the final films exhibited pinhole free morphology and large grain sizes. In addition, the increased precursor concentration after solvent-retarding process led to thick perovskite films. Based on the uniform and thick perovskite films prepared by this convenient process, a champion device efficiency up to 16.8% was achieved. We believe that this simple deposition procedure for high quality perovskite films around micrometer thickness has a great potential in the application of large area perovskite solar cells and other optoelectronic devices.

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  • 324.
    Zajdel, Tom J.
    et al.
    Univ Calif Berkeley, CA 94720 USA; Lawrence Berkeley Natl Lab, CA 94720 USA.
    Baruch, Moshe
    Lawrence Berkeley Natl Lab, CA 94720 USA.
    Méhes, Gábor
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Lawrence Berkeley Natl Lab, CA 94720 USA.
    Stavrinidou, Eleni
    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.
    Maharbiz, Michel M.
    Univ Calif Berkeley, CA 94720 USA; Univ Calif Berkeley, CA 94720 USA; Chan Zuckerberg Biohub, CA USA.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ajo-Franklin, Caroline M.
    Lawrence Berkeley Natl Lab, CA 94720 USA.
    PEDOT:PSS-based Multilayer Bacterial-Composite Films for Bioelectronics2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 15293Article in journal (Refereed)
    Abstract [en]

    Microbial electrochemical systems provide an environmentally-friendly means of energy conversion between chemical and electrical forms, with applications in wastewater treatment, bioelectronics, and biosensing. However, a major challenge to further development, miniaturization, and deployment of bioelectronics and biosensors is the limited thickness of biofilms, necessitating large anodes to achieve sufficient signal-to-noise ratios. Here we demonstrate a method for embedding an electroactive bacterium, Shewanella oneidensis MR-1, inside a conductive three-dimensional poly(3,4-ethylenedioxy thiophene): poly(styrenesulfonate) (PEDOT:PSS) matrix electropolymerized on a carbon felt substrate, which we call a multilayer conductive bacterial-composite film (MCBF). By mixing the bacteria with the PEDOT:PSS precursor in a flow-through method, we maintain over 90% viability of S. oneidensis during encapsulation. Microscopic analysis of the MCBFs reveal a tightly interleaved structure of bacteria and conductive PEDOT:PSS up to 80 mu m thick. Electrochemical experiments indicate S. oneidensis in MCBFs can perform both direct and riboflavin-mediated electron transfer to PEDOT:PSS. When used in bioelectrochemical reactors, the MCBFs produce 20 times more steady-state current than native biofilms grown on unmodified carbon felt. This versatile approach to control the thickness of bacterial composite films and increase their current output has immediate applications in microbial electrochemical systems, including field-deployable environmental sensing and direct integration of microorganisms into miniaturized organic electronics.

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  • 325. Order onlineBuy this publication >>
    Zeglio, Erica
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Self-doped Conjugated Polyelectrolytes for Bioelectronics Applications2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Self-doped conjugated polyelectrolytes (CPEs) are a class of conducting polymers constituted of a π-conjugated backbone and charged side groups. The ionic groups provide the counterions needed to balance the charged species formed in the CPEs backbones upon oxidation. As a result, addition of external counterions is not required, and the CPEs can be defined as selfdoped. The combination of their unique optical and electrical properties render them the perfect candidates for optoelectronic applications. Additionally, their “soft” nature provide for the mechanical compatibility necessary to interface with biological systems, rendering them promising materials for bioelectronics applications. CPEs solubility, aggregation state, and optoelectronic properties can be easily tuned by different means, such as blending or interaction with oppositely charged species (such as surfactants), in order to produce materials with the desired properties. In this thesis both the strategies have been explored to produce new functional materials that can be deposited to form a thin film and,  therefore, used as an active layer in organic electrochemical transistors (OECTs). Microstructure formation of the films as well as influence on devices operation and performance have been investigated. We also show that these methods can be exploited to produce materials whose uniquecombination of self-doping ability and hydrophobicity allows incorporation into the phospholipid double layer of biomembranes, while retaining their properties. As a result, self-doped CPEs can be used both as sensing elements to probe the physical state of biomembranes, and as functional ones providing them with new functionalities, such as electrical conductivity. Integration of conductive electronic biomembranes into OECTs devices has brought us one step forward on the interface of manmade technologies with biological systems.

    List of papers
    1. Conjugated Polyelectrolyte Blends for Electrochromic and Electrochemical Transistor Devices
    Open this publication in new window or tab >>Conjugated Polyelectrolyte Blends for Electrochromic and Electrochemical Transistor Devices
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    2015 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 27, no 18, p. 6385-6393Article in journal (Refereed) Published
    Abstract [en]

    Two self-doped conjugated polyelectrolytes, having semiconducting and metallic behaviors, respectively, have been blended from aqueous solutions in order to produce materials with enhanced optical and electrical properties. The intimate blend of two anionic conjugated polyelectrolytes combine the electrical and optical properties of these, and can be tuned by blend stoichiometry. In situ conductance measurements have been done during doping of the blends, while UV vis and EPR spectroelectrochemistry allowed the study of the nature of the involved redox species. We have constructed an accumulation/depletion mode organic electrochemical transistor whose characteristics can be tuned by balancing the stoichiometry of the active material.

    Place, publisher, year, edition, pages
    AMER CHEMICAL SOC, 2015
    National Category
    Materials Chemistry Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-122212 (URN)10.1021/acs.chemmater.5b02501 (DOI)000361935000028 ()
    Note

    Funding Agencies|Marie Curie network "Renaissance"; Knut and Alice Wallenberg foundation through Wallenberg Scholar grant; Swedish Research Council [VR-2014-3079, D0556101]; Carl Trygger Foundation [CTS 12:206]

    Available from: 2015-10-26 Created: 2015-10-23 Last updated: 2017-12-01
    2. Electronic polymers in lipid membranes
    Open this publication in new window or tab >>Electronic polymers in lipid membranes
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    2015 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, no 11242Article in journal (Refereed) Published
    Abstract [en]

    Electrical interfaces between biological cells and man-made electrical devices exist in many forms, but it remains a challenge to bridge the different mechanical and chemical environments of electronic conductors (metals, semiconductors) and biosystems. Here we demonstrate soft electrical interfaces, by integrating the metallic polymer PEDOT-S into lipid membranes. By preparing complexes between alkyl-ammonium salts and PEDOT-S we were able to integrate PEDOT-S into both liposomes and in lipid bilayers on solid surfaces. This is a step towards efficient electronic conduction within lipid membranes. We also demonstrate that the PEDOT-S@alkyl-ammonium: lipid hybrid structures created in this work affect ion channels in the membrane of Xenopus oocytes, which shows the possibility to access and control cell membrane structures with conductive polyelectrolytes.

    Place, publisher, year, edition, pages
    Nature Publishing Group, 2015
    National Category
    Biophysics
    Identifiers
    urn:nbn:se:liu:diva-120045 (URN)10.1038/srep11242 (DOI)000356090400002 ()26059023 (PubMedID)
    Note

    Funding Agencies|Knut and Alice Wallenberg Foundation; Swedish Research Council

    Available from: 2015-07-06 Created: 2015-07-06 Last updated: 2018-01-25
    3. Conjugated Polyelectrolyte Blend as Photonic Probe of Biomembrane Organization
    Open this publication in new window or tab >>Conjugated Polyelectrolyte Blend as Photonic Probe of Biomembrane Organization
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    2016 (English)In: ChemistrySelect, ISSN 2365-6549, Vol. 1, no 14, p. 4340-4344Article in journal (Refereed) Published
    Abstract [en]

    In the following report, a conjugated polyelectrolyte (CPE) blend has been introduced for the first time as a fluorescent probe of membrane organization. Insertion of the blend into the lipid double layer has been rendered possible through formation of a hydrophobic complex by counterion exchange. Changes in membrane physical state from liquid-disordered (Ldis) to liquid-ordered (Lord), and to solid-ordered (Sord) result in red shifts of blend excitation (up to Δλex=+90 nm) and emission (up to Δλnm=+37 nm) maxima attributable to backbone planarization of CPEs. We found that blend stoichiometry can be adjusted to attain the best interplay among single polyelectrolytes properties, such as sensitivity and luminescence. The resulting probes therefore allow a bimodal detection of membrane physical state: changes in absorption permit a direct visualization of membrane organization, while variations in emission spectra demonstrate that CPE-blends are a promising probes that can be used for imaging applications.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2016
    Keywords
    Conjugated Polyelectrolytes, Fluorescent Probes, Liposomes, Membrane Probes, Polyelectrolytes blend
    National Category
    Biomaterials Science Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-132729 (URN)10.1002/slct.201600920 (DOI)000395422000028 ()
    Note

    Funding agencies: Marie Curie network "Renaissance"; Knut and Alice Wallenberg foundation; DFG [GRK 1640]; Elite Study programme, Macromolecular Science at the University of Bayreuth

    Available from: 2016-11-21 Created: 2016-11-21 Last updated: 2017-04-20Bibliographically approved
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    Self-doped Conjugated Polyelectrolytes for Bioelectronics Applications
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  • 326.
    Zeglio, Erica
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Schmidt, Martina M.
    University of Bayreuth, Germany.
    Thelakkat, Mukundan
    University of Bayreuth, Germany.
    Gabrielsson, Roger
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Soling, Niclas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Conjugated Polyelectrolyte Blends for Highly Stable Accumulation Mode Electrochemical Transistors2017In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 29, no 10, p. 4293-4300Article in journal (Refereed)
    Abstract [en]

    Counterion exchange has been introduced as a method to modify properties of anionic conjugated poly electrolyte (CPE) blends. Blending of two self-doped CPEs having metallic and semiconducting behavior has been achieved from two different solvents, by exchanging the counterion of the metallic component. Different blending conditions lead to films exhibiting different optical properties, depending on the aggregation states of the CPEs. Conductance responses for the blends showed the opportunity to tune threshold voltage of the films both by blending and counterion exchange. Therefore, the blends have been exploited for the fabrication of accumulation mode organic electrochemical transistors. These devices exhibit short switching times and high transconductance, up to 15.3 rnS, as well as high stability upon fast pulsed cycles, retaining 88% of the drain currents after 2 x 10(3) cycles.

  • 327.
    Zeglio, Erica
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Musumeci, Chiara
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ajjan, Fátima
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gabrielsson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Trinh, Xuan thang
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Nguyen, Son Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Maziz, Ali
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Solin, Niclas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Conjugated Polyelectrolyte Blends for Electrochromic and Electrochemical Transistor Devices2015In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 27, no 18, p. 6385-6393Article in journal (Refereed)
    Abstract [en]

    Two self-doped conjugated polyelectrolytes, having semiconducting and metallic behaviors, respectively, have been blended from aqueous solutions in order to produce materials with enhanced optical and electrical properties. The intimate blend of two anionic conjugated polyelectrolytes combine the electrical and optical properties of these, and can be tuned by blend stoichiometry. In situ conductance measurements have been done during doping of the blends, while UV vis and EPR spectroelectrochemistry allowed the study of the nature of the involved redox species. We have constructed an accumulation/depletion mode organic electrochemical transistor whose characteristics can be tuned by balancing the stoichiometry of the active material.

  • 328.
    Zhang, Jiangbin
    et al.
    Univ Cambridge, England; Imperial Coll London, England.
    Kan, Bin
    Nankai Univ, Peoples R China.
    Pearson, Andrew J.
    Univ Cambridge, England.
    Parnell, Andrew J.
    Univ Sheffield, England.
    Cooper, Joshaniel F. K.
    Rutherford Appleton Lab, England.
    Liu, Xiaoke
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. Univ Cambridge, England.
    Conaghan, Patrick J.
    Univ Cambridge, England.
    Hopper, Thomas R.
    Imperial Coll London, England.
    Wu, Yutian
    Univ Cambridge, England.
    Wan, Xiangjian
    Nankai Univ, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Greenham, Neil C.
    Univ Cambridge, England.
    Bakulin, Artem A.
    Imperial Coll London, England.
    Chen, Yongsheng
    Nankai Univ, Peoples R China.
    Friend, Richard H.
    Univ Cambridge, England.
    Correction: Efficient non-fullerene organic solar cells employing sequentially deposited donor–acceptor layers(vol 6, pg 18225, 2018)2018In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 43, p. 21618-21618Article in journal (Refereed)
    Abstract [en]

    Correction for Efficient non-fullerene organic solar cells employing sequentially deposited donor-acceptor layers by Jiangbin Zhang et al., J. Mater. Chem. A, 2018, 6, 18225-18233.

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  • 329.
    Zhang, Jiangbin
    et al.
    Univ Cambridge, England; Imperial Coll London, England.
    Kan, Bin
    Nankai Univ, Peoples R China.
    Pearson, Andrew J.
    Univ Cambridge, England.
    Parnell, Andrew J.
    Univ Sheffield, England.
    Cooper, Joshaniel F. K.
    Rutherford Appleton Lab, England.
    Liu, Xiaoke
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. Univ Cambridge, England.
    Conaghan, Patrick J.
    Univ Cambridge, England.
    Hopper, Thomas R.
    Imperial Coll London, England.
    Wu, Yutian
    Imperial Coll London, England.
    Wan, Xiangjian
    Nankai Univ, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Greenham, Neil C.
    Univ Cambridge, England.
    Bakulin, Artem A.
    Imperial Coll London, England.
    Chen, Yongsheng
    Nankai Univ, Peoples R China.
    Friend, Richard H.
    Univ Cambridge, England.
    Efficient non-fullerene organic solar cells employing sequentially deposited donor-acceptor layers2018In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 37, p. 18225-18233Article in journal (Refereed)
    Abstract [en]

    Non-fullerene acceptors (NFAs) have recently outperformed their fullerene counterparts in binary bulk-heterojunction (BHJ) organic solar cells (OSCs). Further development of NFA OSCs may benefit other novel OSC device structures that alter or extend the standard BHJ concept. Here, we report such a new processing route that forms a BHJ-like morphology between sequentially processed polymer donor and NFA with high power conversion efficiencies in excess of 10%. Both devices show similar charge generation and recombination behaviours, supporting formation of similar BHJ active layers. We correlate the approximate to 30 meV smaller open-circuit voltage in sq-BHJ devices to more substantial non-radiative recombination by voltage loss analysis. We also determine the exciton diffusion length of benchmark polymer PBDB-T to be 10 +/- 3 nm. Our results demonstrate high-efficiency OSC devices using sequential deposition method and provide new opportunities to further improve performance of state-of-the-art OSCs.

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  • 330.
    Zhang, Jie
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ellison, Alexandre
    Okmetic AB, Linköping, Sweden.
    Danielsson, Örjan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Linnarsson, M. K.
    Royal Institute of Technology ( KTH), Stockholm, Sweden.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Epitaxial growth of 4H SiC in a vertical hot-wall CVD reactor: Comparison between up- and down-flow orientations2002In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 241, no 4, p. 421-430Article in journal (Refereed)
    Abstract [en]

    The CVD growth of 4H SiC is investigated in a vertical hot-wall reactor in both up-flow (the chimney reactor) and down-flow (the inverted chimney) orientations. The growth rate and the nitrogen doping are studied for comparison. Under the investigated process conditions the growth mechanism is shown to be similar in these two reactor orientations. Only slight difference is observed in the temperature effect depending on the flow direction. Both reactor types have produced epilayers with high growth rates (10–35 μm/h) and low residual n-type doping (low 1016 down to mid 1013 cm−3) with comparable morphology. Dimensionless flow numbers are used to provide a qualitative analysis of the flow and heat transfer mechanisms in the vertical hot-wall system. Two-dimensional numerical simulation in a cylindrical geometry is conducted to demonstrate the flow and temperature profile with selected process parameters. Comparison of the experimental results in the chimney and the inverted chimney is performed to give insight into the fast epitaxial hot-wall growth.

  • 331.
    Zhang, Ri-Chao
    et al.
    Zhejiang University, Peoples R China; Queens University of Belfast, North Ireland; University of Ulster, North Ireland.
    Sun, Dan
    Queens University of Belfast, North Ireland.
    Lu, Ai
    China Academic Engn Phys, Peoples R China.
    Askari Ghotbabadi, Sadegh
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Macias-Montero, Manuel
    University of Ulster, North Ireland.
    Joseph, Paul
    Victoria University, Australia.
    Dixon, Dorian
    University of Ulster, North Ireland.
    Ostrikov, Kostya
    Queensland University of Technology, Australia; CSIRO, Australia.
    Maguire, Paul
    University of Ulster, North Ireland.
    Mariotti, Davide
    University of Ulster, North Ireland.
    Microplasma Processed Ultrathin Boron Nitride Nanosheets for Polymer Nanocomposites with Enhanced Thermal Transport Performance2016In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, no 21, p. 13567-13572Article in journal (Refereed)
    Abstract [en]

    This Research Article reports on the enhancement of the thermal transport properties of nanocomposite materials containing hexagonal boron nitride in poly(vinyl alcohol) through room-temperature atmospheric pressure direct-current microplasma processing. Results show that the microplasma treatment leads to exfoliation of the hexagonal boron nitride in isopropyl alcohol, reducing the number of stacks from amp;gt;30 to a few or single layers. The thermal diffusivity of the resulting nanocomposites reaches 8.5 mm(2) s(-1) times greater than blank poly(vinyl alcohol) and twice that of nanocomposites containing nonplasma treated boron nitride nanosheets. From TEM analysis, we observe much less aggregation Of the nanosheets after plasma processing along with indications of an amorphous carbon interfacial layer, which may contribute to stable dispersion of boron nitride nanosheets in the resulting plasma treated colloids.

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  • 332.
    Zhang, Ri-Chao
    et al.
    East China Jiaotong University, Peoples R China; Queens University, North Ireland; University of Ulster, North Ireland; University of Loughborough, England.
    Sun, Dan
    Queens University, North Ireland.
    Zhang, Ruirui
    East China Jiaotong University, Peoples R China; Queens University, North Ireland; University of Ulster, North Ireland; University of Loughborough, England.
    Lin, Wen-Feng
    University of Loughborough, England.
    Macias-Montero, Manuel
    University of Ulster, North Ireland.
    Patel, Jenish
    Marwadi Educ Fdn Grp Institute, India.
    Askari Ghotbabadi, Sadegh
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    McDonald, Calum
    University of Ulster, North Ireland.
    Mariotti, Davide
    University of Ulster, North Ireland.
    Maguire, Paul
    University of Ulster, North Ireland.
    Gold nanoparticle-polymer nanocomposites synthesized by room temperature atmospheric pressure plasma and their potential for fuel cell electrocatalytic application2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 46682Article in journal (Refereed)
    Abstract [en]

    Conductive polymers have been increasingly used as fuel cell catalyst support due to their electrical conductivity, large surface areas and stability. The incorporation of metal nanoparticles into a polymer matrix can effectively increase the specific surface area of these materials and hence improve the catalytic efficiency. In this work, a nanoparticle loaded conductive polymer nanocomposite was obtained by a one-step synthesis approach based on room temperature direct current plasmaliquid interaction. Gold nanoparticles were directly synthesized from HAuCl4 precursor in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS). The resulting AuNPs/PEDOT: PSS nanocomposites were subsequently characterized under a practical alkaline direct ethanol fuel cell operation condition for its potential application as an electrocatalyst. Results show that AuNPs sizes within the PEDOT: PSS matrix are dependent on the plasma treatment time and precursor concentration, which in turn affect the nanocomposites electrical conductivity and their catalytic performance. Under certain synthesis conditions, unique nanoscale AuNPs/PEDOT: PSS core-shell structures could also be produced, indicating the interaction at the AuNPs/polymer interface. The enhanced catalytic activity shown by AuNPs/PEDOT: PSS has been attributed to the effective electron transfer and reactive species diffusion through the porous polymer network, as well as the synergistic interfacial interaction at the metal/polymer and metal/metal interfaces.

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  • 333.
    Zhang, Shuai
    et al.
    West Pomeranian Univ Technol, Poland.
    Shi, Xiaoze
    West Pomeranian Univ Technol, Poland.
    Chen, Xuecheng
    West Pomeranian Univ Technol, Poland; Chinese Acad Sci, Peoples R China.
    Zhang, Dengsong
    Shanghai Univ, Peoples R China.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Zhang, Zhibin
    Uppsala Univ, Sweden.
    Chu, Paul K.
    City Univ Hong Kong, Peoples R China; City Univ Hong Kong, Peoples R China.
    Tang, Tao
    Chinese Acad Sci, Peoples R China.
    Mijowska, Ewa
    West Pomeranian Univ Technol, Poland.
    Large-Scale and Low-Cost Motivation of Nitrogen-Doped Commercial Activated Carbon for High-Energy-Density Supercapacitor2019In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, no 6, p. 4234-4243Article in journal (Refereed)
    Abstract [en]

    The growing requirement for high-performance energy-storage devices has spurred the development of supercapacitors, but the low energy density remains a technical hurdle. In this work, porous nitrogen-doped activated carbon (NAC) is prepared on a large scale from commercial activated carbon (AC) and inexpensive chemicals by a one-step method. The NAC material with 3.1 wt % nitrogen has a high specific surface area of 1186 m(2) g(-1) and shows a specific capacitance of 427 F g(-1) in a symmetric cell with an aqueous electrolyte. 98.2% of the capacity is reserved after 20 000 cycles at 20 A g(-1). The energy densities of the NAC are 17.2 and 87.8 Wh kg(-1) in acidic and organic electrolytes, respectively. Moreover, this simple process is readily scalable to address commercial demand and can be extended to the motivation of a variety of carbon based materials with poor capacitances.

  • 334.
    Zhang, Shucan
    et al.
    Chinese Academic Science, Peoples R China.
    Wang, Zhenyu
    Chinese Academic Science, Peoples R China.
    Guo, Peng
    Chinese Academic Science, Peoples R China.
    Ke, Peiling
    Chinese Academic Science, Peoples R China.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Wang, Aiying
    Chinese Academic Science, Peoples R China.
    Temperature induced superhard CrB2 coatings with preferred (001) orientation deposited by DC magnetron sputtering technique2017In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 322, p. 134-140Article in journal (Refereed)
    Abstract [en]

    The influence of deposition temperature in the range of 100 degrees C to 400 degrees C on the microstructure and mechanical properties of CrB2 coatings by DC magnetron sputtering was studied. The coating texture changed from random mixed orientation with (101) and (001) planes to the preferred (001) orientation when increasing the deposition temperature. Moreover, the microstructure coating evolved from an underdense structure to a bulky columnar structure (similar to 50 nm), and finally to a dense nanoscale columnar structure (similar to 7 nm). This structural densification was mainly attributed to the enhanced atomic surface diffusion with increasing deposition temperature. It resulted in promotion of the (001) preferred orientation and greatly enhanced the mechanical properties. Specifically, when the deposition temperature was 300 degrees C, the CrB2 coatings exhibited the highest toughness while superhardness (51 +/- 2 GPa) was achieved for coating grown at 400 degrees C. (C) 2017 Published by Elsevier B.V.

  • 335.
    Zhang, Xuanjun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Wang, Wenjing
    Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, China.
    Hu, Zhangjun
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Wang, Guannan
    Liaoning Medical University, China.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Coordination polymers for energy transfer: Preparations, properties, sensing applications, and perspectives2015In: Coordination chemistry reviews, ISSN 0010-8545, E-ISSN 1873-3840, Vol. 284, p. 206-235Article, review/survey (Refereed)
    Abstract [en]

    This review highlights the recent progress of bulk and nanoscale coordination polymer (CP) materials forenergy transfer. Artificial light-harvesting materials with efficient energy transfer are practically usefulfor a variety of applications including photovoltaic, white emitting devices, and sensors. In the pastdecades CP (aka Metal-organic framework, MOF) has experienced rapid development due to a multitude of applications, including catalyst, gas storage and separations, non-linear optics, luminescence, and soon. Recent research has shown that CP is a very promising light-harvesting platform because the energytransfers can occur between different ligands, from ligand to metal centers, or from MOF skeleton to guestspecies. This review comprehensively surveyed synthetic approaches to light-harvesting CPs, and postfunctionalization. Sensing applications and achievements in energy-transfer CP nanoparticles and thinfilms were also discussed.

  • 336.
    Zheng, Xiaopeng
    et al.
    KAUST, Saudi Arabia.
    Hou, Yi
    Univ Toronto, Canada.
    Bao, Chunxiong
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Yin, Jun
    KAUST, Saudi Arabia.
    Yuan, Fanglong
    Univ Toronto, Canada.
    Huang, Ziru
    University of Toronto, Toronto, Ontario, Canada.
    Song, Kepeng
    KAUST, Saudi Arabia.
    Liu, Jiakai
    KAUST, Saudi Arabia.
    Troughton, Joel
    KAUST, Saudi Arabia.
    Gasparini, Nicola
    KAUST, Saudi Arabia.
    Zhou, Chun
    Univ Toronto, Canada.
    Lin, Yuanbao
    KAUST, Saudi Arabia.
    Xue, Ding-Jiang
    Univ Toronto, Canada.
    Chen, Bin
    Univ Toronto, Canada.
    Johnston, Andrew K.
    Univ Toronto, Canada.
    Wei, Nini
    KAUST, Saudi Arabia.
    Hedhili, Mohamed Nejib
    KAUST, Saudi Arabia.
    Wei, Mingyang
    Univ Toronto, Canada.
    Alsalloum, Abdullah Y.
    KAUST, Saudi Arabia.
    Maity, Partha
    KAUST, Saudi Arabia.
    Turedi, Bekir
    KAUST, Saudi Arabia.
    Yang, Chen
    KAUST, Saudi Arabia.
    Baran, Derya
    KAUST, Saudi Arabia.
    Anthopoulos, Thomas D.
    KAUST, Saudi Arabia.
    Han, Yu
    KAUST, Saudi Arabia.
    Lu, Zheng-Hong
    Univ Toronto, Canada.
    Mohammed, Omar F.
    KAUST, Saudi Arabia.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sargent, Edward H.
    Univ Toronto, Canada.
    Bakr, Osman M.
    KAUST, Saudi Arabia.
    Managing grains and interfaces via ligand anchoring enables 22.3%-efficiency inverted perovskite solar cells2020In: NATURE ENERGY, ISSN 2058-7546, Vol. 5, p. 131-140Article in journal (Refereed)
    Abstract [en]

    Inverted perovskite solar cells have attracted increasing attention because they have achieved long operating lifetimes. However, they have exhibited significantly inferior power conversion efficiencies compared to regular perovskite solar cells. Here we reduce this efficiency gap using a trace amount of surface-anchoring alkylamine ligands (AALs) with different chain lengths as grain and interface modifiers. We show that long-chain AALs added to the precursor solution suppress nonradiative carrier recombination and improve the optoelectronic properties of mixed-cation mixed-halide perovskite films. The resulting AAL surface-modified films exhibit a prominent (100) orientation and lower trap-state density as well as enhanced carrier mobilities and diffusion lengths. These translate into a certified stabilized power conversion efficiency of 22.3% (23.0% power conversion efficiency for lab-measured champion devices). The devices operate for over 1,000 h at the maximum power point under simulated AM1.5 illumination, without loss of efficiency. While perovskite solar cells with an inverted architecture hold great promise for operation stability, their power conversion efficiency lags behind that of conventional cells. Here, Zheng et al. achieve a certified 22.34% efficiency, exploiting alkylamine ligands as grain and interface modifiers.

  • 337.
    Zhirkov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Polcik, Peter
    Plansee Composite Mat GmbH, Germany.
    Kolozsvari, Szilard
    Plansee Composite Mat GmbH, Germany.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Macroparticle generation in DC arc discharge from a WC cathode2017In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, no 10, article id 103305Article in journal (Refereed)
    Abstract [en]

    We have studied macroparticle generation from a tungsten carbide cathode used in a dc vacuum arc discharge. Despite a relatively high decomposition/ melting point (similar to 3100 K), there is an intensive generation of visible particles with sizes in the range 20-35 mu m. Visual observations during the discharge and scanning electron microscopy of the cathode surface and of collected macroparticles indicate a new mechanism for particle formation and acceleration. Based on the W-C phase diagram, there is an intensive sublimation of carbon from the melt resulting from the cathode spot. The sublimation supports the formation of a sphere, which is accelerated upon an explosion initiated by Joule heating at the critical contact area between the sphere and the cathode body. The explosive nature of the particle acceleration is confirmed by surface features resembling the remains of a splash on the droplet surface. Published by AIP Publishing.

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  • 338.
    Zhou, Jie
    et al.
    Chinese Academic Science, Peoples R China; University of Chinese Academic Science, Peoples R China.
    Zha, Xianhu
    Chinese Academic Science, Peoples R China.
    Zhou, Xiaobing
    Chinese Academic Science, Peoples R China.
    Chen, Fanyan
    Chinese Academic Science, Peoples R China.
    Gao, Guoliang
    Chinese Academic Science, Peoples R China.
    Wang, Shuwei
    Chinese Academic Science, Peoples R China.
    Shen, Cai
    Chinese Academic Science, Peoples R China.
    Chen, Tao
    Chinese Academic Science, Peoples R China.
    Zhi, Chunyi
    City University of Hong Kong, Peoples R China.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Du, Shiyu
    Chinese Academic Science, Peoples R China.
    Xue, Jianming
    Peking University, Peoples R China.
    Shi, Weiqun
    Chinese Academic Science, Peoples R China; Chinese Academic Science, Peoples R China.
    Chai, Zhifang
    Chinese Academic Science, Peoples R China; Chinese Academic Science, Peoples R China.
    Huang, Qing
    Chinese Academic Science, Peoples R China.
    Synthesis and Electrochemical Properties of Two-Dimensional Hafnium Carbide2017In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 11, no 4, p. 3841-3850Article in journal (Refereed)
    Abstract [en]

    We demonstrate fabrication of a two-dimensional Hf-containing MXene, Hf3C2Tz, by selective etching of a layered parent Hf-3[Al(Si)](4)C-6 compound. A substitutional solution of Si on Al sites effectively weakened the interfacial adhesion between Hf-C and Al(Si)-C sublayers within the unit cell of the parent compound, facilitating the subsequent selective etching. The underlying mechanism of the Si-alloying-facilitated etching process is thoroughly studied by first-principles density functional calculations. The result showed that more valence electrons of Si than Al weaken the adhesive energy of the etching interface. The MXenes were determined to be flexible and conductive. Moreover, this 2D Hf-containing MXene material showed reversible volumetric capacities of 1567 and 504 mAh cm(-3) for lithium and sodium ions batteries, respectively, at a current density of 200 mAg(-1) after 200 cycles. Thus, Hf3C2Tz MXenes with a 2D structure are candidate anode materials for metal-ion intercalation, especially for applications where size matters.

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  • 339.
    Zhou, Ruimin
    et al.
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China; Univ Copenhagen, Denmark; Univ Copenhagen, Denmark.
    Jiang, Zhaoyan
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Yang, Chen
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Yu, Jianwei
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Feng, Jirui
    Xi An Jiao Tong Univ, Peoples R China.
    Adil, Muhammad Abdullah
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Deng, Dan
    Natl Ctr Nanosci and Technol, Peoples R China.
    Zou, Wenjun
    Natl Ctr Nanosci and Technol, Peoples R China.
    Zhang, Jianqi
    Natl Ctr Nanosci and Technol, Peoples R China.
    Lu, Kun
    Natl Ctr Nanosci and Technol, Peoples R China.
    Ma, Wei
    Xi An Jiao Tong Univ, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wei, Zhixiang
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    All-small-molecule organic solar cells with over 14% efficiency by optimizing hierarchical morphologies2019In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, article id 5393Article in journal (Refereed)
    Abstract [en]

    The high efficiency all-small-molecule organic solar cells (OSCs) normally require optimized morphology in their bulk heterojunction active layers. Herein, a small-molecule donor is designed and synthesized, and single-crystal structural analyses reveal its explicit molecular planarity and compact intermolecular packing. A promising narrow bandgap small-molecule with absorption edge of more than 930 nm along with our home-designed small molecule is selected as electron acceptors. To the best of our knowledge, the binary all-small-molecule OSCs achieve the highest efficiency of 14.34% by optimizing their hierarchical morphologies, in which the donor or acceptor rich domains with size up to ca. 70 nm, and the donor crystals of tens of nanometers, together with the donor-acceptor blending, are proved coexisting in the hierarchical large domain. All-small-molecule photovoltaic system shows its promising for high performance OSCs, and our study is likely to lead to insights in relations between bulk heterojunction structure and photovoltaic performance.

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  • 340.
    Zuo, Guangzheng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    Andersson, Olof
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    Abdalla, Hassan
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    Kemerink, Martijn
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    High thermoelectric power factor from multilayer solution-processed organic films2018In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 112, no 8, article id 083303Article in journal (Refereed)
    Abstract [en]

    We investigate the suitability of the "sequential doping" method of organic semiconductors for thermoelectric applications. The method consists of depositing a dopant (F4TCNQ) containing solution on a previously cast semiconductor (P3HT) thin film to achieve high conductivity, while preserving the morphology. For very thin films (similar to 25 nm), we achieve a high power factor around 8 mu W/mK(-2) with a conductivity over 500 S/m. For the increasing film thickness, conductivity and power factor show a decreasing trend, which we attribute to the inability to dope the deeper parts of the film. Since thick films are required to extract significant power from thermoelectric generators, we developed a simple additive technique that allows the deposition of an arbitrary number of layers without significant loss in conductivity or power factor that, for 5 subsequent layers, remain at similar to 300 S/m and similar to 5 mu W/mK(-2), respectively, whereas the power output increases almost one order of magnitude as compared to a single layer. The efficient doping in multilayers is further confirmed by an increased intensity of (bi)polaronic features in the UV-Vis spectra. Published by AIP Publishing.

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