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  • 151.
    Muller, Christian
    et al.
    Esfera UAB.
    Bergqvist, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vandewal, Koen
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Anselmo, Ana Sofia
    Karlstads University.
    Magnusson, Roger
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Alonso, M .Isabel
    Esfera UAB.
    Moons, Ellen
    Karlstads University.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Campoy-Quiles, Mariano
    Esfera UAB.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Phase behaviour of liquid-crystalline polymer/fullerene organic photovoltaic blends: thermal stability and miscibility2011In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, no 29, p. 10676-10684Article in journal (Refereed)
    Abstract [en]

    The thermal behaviour of an organic photovoltaic (OPV) binary system comprised of a liquid-crystalline fluorene-based polymer and a fullerene derivative is investigated. We employ variable-temperature ellipsometry complemented by photo-and electroluminescence spectroscopy as well as optical microscopy and scanning force nanoscopy to explore phase transitions of blend thin films. The high glass transition temperature correlates with the good thermal stability of solar cells based on these materials. Furthermore, we observe partial miscibility of the donor and acceptor together with the tendency of excess fullerene derivative to segregate into exceedingly large domains. Thus, for charge generation less adequate bulk-heterojunction nanostructures are poised to develop if this mixture is exposed to more elevated temperatures. Gratifyingly, the solubility of the fullerene derivative in the polymer phase is found to decrease if a higher molecular-weight polymer fraction is employed, which offers routes towards improving the photovoltaic performance of non-crystalline OPV blends.

  • 152.
    Solin, Niclas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Bäcklund, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Preparation of amyloid-like materials functionalized with hydrophobic molecules2011In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 242, p. 526-ORGN-Article in journal (Other academic)
    Abstract [en]

    When exposed to acid and heat, insulin is known to self into fibril-like structures known as amyloid. These nanowires can be used as templates in materials science applications. We have developed methods that allow us to functionalize such nanowires with phosphorescent metal-complexes (Chem. Eur. J. 2010, 16, 4190). The method involves mixing the metal complex and the protein in the solid state, followed by self assembly of the resulting composite material. We were able to succesfully incorporate these materials into white OLEDs (Nano Lett. 2010, 10, 2225). We have now developed the method further to include various types of materials and molecules. We have also found that certain molecules might have dramatic effect on the self-assembly process, resulting in novel amyloid-based materials.

  • 153.
    Wang, Ergang
    et al.
    Chalmers.
    Hou, Lintao
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wang, Zhongqiang
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Ma, Zaifei
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hellstrom, Stefan
    Chalmers.
    Zhuang, Wenliu
    Chalmers.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Side-Chain Architectures of 2,7-Carbazole and Quinoxaline-Based Polymers for Efficient Polymer Solar Cells2011In: MACROMOLECULES, ISSN 0024-9297, Vol. 44, no 7, p. 2067-2073Article in journal (Refereed)
    Abstract [en]

    Three polymers bearing a common carbazole thiophene quinoxaline thiophene backbone, but different side chains, were designed and synthesized in order to investigate the effect of side chains on their photovoltaic performance. Their photophysical, electrochemical, and photovoltaic properties were investigated and compared. The polymer EWC3, with the largest amount of side chains, showed the highest power conversion efficiency of 3.7% with an open-circuit voltage (V-oc) of 0.92 V. The atomic force microscopy images of the active layers of the devices showed that the morphology was highly influenced by the choice of the solvent and processing additive. It is worth noting that polymer solar cells (PSCs) fabricated from EWC3, with branched side chains on the carbazole units, gave a much higher V-oc than the devices made from EWC1, which bears the same electron-deficient segment as EWC3 but straight side chains on carbazole units. This study offered a useful and important guideline for designing 2,7-carbazole-based polymers for high-performance PSCs.

  • 154.
    Li, Weiwei
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Viktor
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Thomann, Yi
    Freiburg Material Research Centre, Germany.
    Veit, Clemens
    Fraunhofer Institute for Solar Energy Systems, Germany.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Qin, Ruiping
    Beijing Normal University, China.
    Bo, Zhishan
    Beijing Normal University, China.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wuerfel, Uli
    Freiburg Material Research Centre, Germany.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    The Effect of additive on performance and shelf-stability of HSX-1/PCBM photovoltaic devices2011In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 12, no 9, p. 1544-1551Article in journal (Refereed)
    Abstract [en]

    How 1,8-diiodooctane (DIO) enhances performance of polymer solar cells based on polymer HXS-1 and fullerene [6,6]-phenyl C(71)-butyric acid methyl ester (PC(71)BM) from 3.6% to 5.4% is scrutinized with several techniques by comparing devices or blend films spin-coated from dichlorobenzene (DCB) to those from DCB/DIO (97.5:2.5 v/v). Morphology of blend films is examined with atomic force microscopy (AFM), transmission electron microscopy (TEM) and electron tomography (3-D TEM), respectively. Charge generation and recombination is studied with photoluminescence, and charge transport with field effect transistors. The morphology with domain size in 10-20 nm and vertical elongated clusters formed in DIO system is supposed to facilitate charge transport and minimize charge carrier recombination, which are the main reasons for enhancing power conversion efficiency (PCE) from 3.6% (without DIO) to 5.4% (with DIO). Furthermore, a two year inspection shows no significant impact of DIO on the shelf-stability of the solar cells. No visible degradation in the second year indicates that the morphology of the active layers in the devices is relatively stable after initial relaxation in the first year.

  • 155.
    Müller, Christian
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hamedi, Mahiar
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Karlsson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jansson, Ronnie
    Biomed Centre, SLU.
    Marcilla, Rebeca
    CIDETEC Centre Electrochem Technology.
    Hedhammar, My
    Biomed Centre, SLU.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Woven Electrochemical Transistors on Silk Fibers2011In: ADVANCED MATERIALS, ISSN 0935-9648, Vol. 23, no 7, p. 898-Article in journal (Refereed)
    Abstract [en]

    Woven electrochemical transistors on silk fibers from the silkworm Bombyx mori are demonstrated. This is achieved with carefully chosen electrolyte chemistry: electrically conducting silk fibers are produced by dyeing silk fibers with a conjugated polyelectrolyte and gating is accomplished by use of an electrolyte mixture composed of imidazolium-based ionic liquids.

  • 156.
    Wang, Ergang
    et al.
    Chalmers.
    Hou, Lintao
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wang, Zhongqiang
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Hellstrom, Stefan
    Chalmers.
    Zhang, Fengling
    Chalmers.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    An Easily Synthesized Blue Polymer for High-Performance Polymer Solar Cells2010In: ADVANCED MATERIALS, ISSN 0935-9648, Vol. 22, no 46, p. 5240-5244Article in journal (Refereed)
    Abstract [en]

    High performance solar cells fabricated from an easily synthesized donor-acceptor polymer show maximum power point up to 6.0 mW cm(-2), with an open-circuit voltage of 0.89 V, short-circuit current density of 10.5 mA cm(-2) and fill factor of 0.64, making this polymer a particularly promising candidate for high-efficiency low-cost polymer solar cells.

  • 157.
    Björk, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Herland, Anna
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Hamedi, Mahiar
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Biomolecular nanowires decorated by organic electronic polymers2010In: JOURNAL OF MATERIALS CHEMISTRY, ISSN 0959-9428, Vol. 20, no 12, p. 2269-2276Article in journal (Refereed)
    Abstract [en]

    We demonstrate the shaping and forming of organic electronic polymers into designer nanostructures using biomacromolecules. In order to create nanowires, nanohelixes and assemblies of these, we coordinate semiconducting or metallic polymers to biomolecular polymers in the form of DNA and misfolded proteins. Optoelectronic and electrochemical devices utilizing these shaped materials are discussed.

  • 158.
    Gadisa, Abay
    et al.
    Hasselt University.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Vandewal, Koen
    Hasselt University.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    V Manca, Jean
    Hasselt University.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Bipolar Charge Transport in Fullerene Molecules in a Bilayer and Blend of Polyfluorene Copolymer and Fullerene2010In: ADVANCED MATERIALS, ISSN 0935-9648, Vol. 22, no 9, p. 1008-Article in journal (Refereed)
    Abstract [en]

    Efficient polymer solar cells typically contain the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), which promotes dissociation of excited states and enhances charge transport. The ability of PCBM to transport holes in solar cell bulk heterojunction films is monitored via the electroluminescence emission of a bulk heterojunction blend of PCBM and a polyfluorene copolymer. In polymer/fullerene bilayer diodes, fullerene emission is also observed.

  • 159.
    Zhou, Yi
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Antenehe Gedefaw, Desta
    University of Addis Ababa.
    Hellstrom, Stefan
    Chalmers.
    Kratschmer, Ilse
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Mammo, Wendimagegn
    University of Addis Ababa.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Black Polymers in Bulk-Heterojunction Solar Cells2010In: IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, ISSN 1077-260X, Vol. 16, no 6, p. 1565-1572Article in journal (Refereed)
    Abstract [en]

    The active materials in polymer solar cells have a decisive role on the performance of the cells. Polymers with extended absorption, i.e., black polymers with absorption covering the whole visible region are desired in order to capture the important parts of the solar irradiation. Different ways of achieving black active materials are discussed and two new alternating polyfluorene (APFO) copolymers with broad absorption, APFO-Black 1 and APFO-Black 2, using two different design strategies are described. The UV-Vis absorption spectra of the polymers extend to approximately 850 nm, and the polymers were used as donors and [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM)[60] or PCBM[70] as acceptors in solar cell devices in various mixing ratios. The best combinations yielded an overall power conversion efficiency of 1.2% for APFO-Black 1 and 1.5% for APFO-Black 2.

  • 160.
    Lorrmann, J
    et al.
    University Wurzburg.
    Badada, B H
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Dyakonov, V
    University Wurzburg.
    Deibel, C
    University Wurzburg.
    Charge carrier extraction by linearly increasing voltage: Analytic framework and ambipolar transients2010In: JOURNAL OF APPLIED PHYSICS, ISSN 0021-8979, Vol. 108, no 11, p. 113705-Article in journal (Refereed)
    Abstract [en]

    Up to now the basic theoretical description of charge extraction by linearly increasing voltage (CELIV) is solved for a low conductivity approximation only. Here we present the full analytical solution, thus generalize the theoretical framework for this method. We compare the analytical solution and the approximated theory, showing that especially for typical organic solar cell materials the latter approach has a very limited validity. Photo-CELIV measurements on poly(3-hexyl thiophene-2,5-diyl):[6,6]-phenyl-C-61 butyric acid methyl ester based solar cells were then evaluated by fitting the current transients to the analytical solution. We found that the fit results are in a very good agreement with the experimental observations, if ambipolar transport is taken into account, the origin of which we will discuss. Furthermore we present parametric equations for the mobility and the charge carrier density, which can be applied over the entire experimental range of parameters.

  • 161.
    Vandewal, Koen
    et al.
    Hasselt University.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Manca, Jean V
    Hasselt University.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Charge-Transfer States and Upper Limit of the Open-Circuit Voltage in Polymer: Fullerene Organic Solar Cells2010In: IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, ISSN 1077-260X, Vol. 16, no 6, p. 1676-1684Article in journal (Refereed)
    Abstract [en]

    The power conversion efficiency of polymer: fullerene bulk heterojunction solar cells depends on the generated photocurrent and photovoltage. Here we show, using the thermodynamic theory of detailed balance, that the photovoltage in particular is limited by the presence of polymer: fullerene material interaction, resulting in the formation of a weak donor-acceptor charge transfer complex (CTC). Excited CTCs, or charge transfer (CT) states, are visible in highly sensitive measurements of the absorption and photovoltaic action spectrum, or in photoluminescence and electroluminescence measurements. It is shown that photovoltaic and electroluminescent actions of the polymer: fullerene CTC are related by a reciprocity relation. This relation reproduces the measured open-circuit voltage (V-oc) of the photovoltaic device under solar conditions. Also, the temperature and illumination intensity dependence of V-oc is reproduced by the theory. Assuming perfect conditions for charge generation and recombination, a maximum obtainable V-oc value in function of polymer: fullerene CTC properties is derived.

  • 162.
    Wigenius, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Magnusson, Karin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Björk, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Olof
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    DNA Chips with Conjugated Polyelectrolytes in Resonance Energy Transfer Mode2010In: LANGMUIR, ISSN 0743-7463, Vol. 26, no 5, p. 3753-3759Article in journal (Refereed)
    Abstract [en]

    We show how to use well-defined conjugated polyelectrolytes (CPEs) combined With Surface energy patterning to Fabricate DNA Chips utilizing A fluorescence signal amplification. Cholesterol-modified DNA strands in complex with it CPE are adsorbed to a surface energy pattern, formed by printing with soft elastomer stamps. Hybridization of the surface bound DNA strands with it short complementary strand from Solution is monitored using both fluorescence microscopy and imaging surface plasmon resonance. The CPEs act as antennas, enhancing resonance energy transfer to the dye-labeled DNA when complementary hybridization of the double strand occurs.

  • 163.
    Asplund, Maria
    et al.
    Royal Institute of Technology.
    Nyberg, Tobias
    Royal Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Electroactive polymers for neural interfaces2010In: POLYMER CHEMISTRY, ISSN 1759-9954, Vol. 1, no 9, p. 1374-1391Article, review/survey (Refereed)
    Abstract [en]

    Development of electroactive conjugated polymers, for the purpose of recording and eliciting signals in the neural systems in humans, can be used to fashion the interfaces between the two signalling systems of electronics and neural systems. The design of desirable chemical, mechanical and electrical properties in the electroactive polymer electrodes, and the means of integration of these into biological systems, are here reviewed.

  • 164.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    From Metal to Semiconductor and Back: Thirty Years of Conjugated Polymer Electrochemistry2010In: Iontronics: Ionic Carriers in Organic Electronic Materials and Devices / [ed] Janelle Leger, Magnus Berggren, Sue Carter, Boca Raton: CRC Press; Taylor & Francis Group , 2010, p. 29-41Chapter in book (Other academic)
    Abstract [en]

    The field of organic electronics promises exciting new technologies based on inexpensive and mechanically flexible electronic devices, and is now seeing the beginning of commercial success. On the sidelines of this increasingly well-established field are several emerging technologies with innovative mechanisms and functions that utilize the mixed ionic/electronic conducting character of conjugated organic materials. Iontronics: Ionic Carriers in Organic Electronic Materials and Devices explores the potential of these materials, which can endow electronic devices with unique functionalities.

    Fundamental science and applications

    With contributions from a community of experts, the book focuses on the use of ionic functions to define the principle of operation in polymer devices. It begins by reviewing the scientific understanding and important scientific discoveries in the electrochemistry of conjugated polymers. It examines the known effects of ion incorporation, including the theory and modulation of electrochemistry in polymer films, and it explores the coupling of electronic and ionic transport in polymer films. The authors also describe applications that use this technology, including polymer electrochromic devices, artificial muscles, light-emitting electrochemical cells, and biosensors, and they discuss the fundamental technological hurdles in these areas.

    The changes in materials properties and device characteristics due to ionic conductivity and electrochemical doping in electrically conductive organic materials, as well as the importance of these processes in a number of different and exciting technologies, point to a large untapped potential in the development of new applications and novel device architecture. This volume captures the state of the science in this burgeoning field.

  • 165.
    Pal, Suman Kalyan
    et al.
    Chemical Physics, Lund University.
    Kesti, Tero
    University of Oulu, Finland.
    Maiti, Manisankar
    Chemical Physics, Lund University.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Hellström, Stefan
    Chalmers University of Technology.
    Andersson, Mats R
    Chalmers University of Technology.
    Oswald, Frederic
    Universidad de Castilla-La Mancha.
    Langa, Fernando
    Universidad de Castilla-La Mancha.
    Österman, Tomas
    Chemical Physics, Lund University:.
    Pascher, Torbjo¨rn
    Chemical Physics, Lund University.
    Yartsev, Arkady
    Chemical Physics, Lund University.
    Sundström, Villy
    Chemical Physics, Lund University.
    Geminate Charge Recombination in Polymer/Fullerene Bulk Heterojunction Films and Implications for Solar Cell Function2010In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 35, p. 12440-12451Article in journal (Refereed)
    Abstract [en]

    We have studied the influence of three different fullerene derivatives on the charge generation and recombination dynamics of polymer/fullerene bulk heterojunction (BHJ) solar cell blends. Charge generation in APFO3/[70]PCBM and APFO3/[60]PCBM is very similar and somewhat slower than charge generation in APFO3/[70]BTPF. This difference qualitatively matches the trend in free energy change of electron transfer estimated from the LUMO energies of the polymer and fullerene derivatives. The first order (geminate) charge recombination rate is significantly different for the three fullerene derivatives studied and increases in the order APFO3/[70]PCBM andlt; APFO3/[60]PCBM andlt; APFO3/[70]BTPF. The variation in electron transfer rate cannot be explained from the LUMO energies of the fullerene derivatives and single-step electron transfer in the Marcus inverted region and simple considerations of expected trends for the reorganization energy and free energy change. Instead we suggest that geminate charge recombination occurs from a state where electrons and holes have separated to different distances in the various materials because of an initially high charge mobility, different for different materials. In a BHJ thin film this charge separation distance is not sufficient to overcome the electrostatic attraction between electrons and holes and geminate recombination occurs on the nanosecond to hundreds of nanoseconds time scale. In a BHJ solar cell, we suggest that the internal electric field in combination with polarization effects and the dynamic nature of polarons are key features to overcome electron-hole interactions to form free extractable charges.

  • 166.
    Tang, Qun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. 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.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Hybrid bioinorganic insulin amyloid fibrils2010In: CHEMICAL COMMUNICATIONS, ISSN 1359-7345, Vol. 46, no 23, p. 4157-4159Article in journal (Refereed)
    Abstract [en]

    Herein we report a method to functionalize in vitro grown insulin amyloid fibrils with various inorganic materials. The counterion of the positively charged amyloid fibril is exchanged with anions from various salts; subsequent addition of appropriate cations results in functionalization of the amyloid fibril. We demonstrate the formation of apatite and platinum complex structures ordered by the amyloid template.

  • 167.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Hybrid electronics and electrochemistry with conjugated polymers2010In: Chemical Society Reviews, ISSN 0306-0012, E-ISSN 1460-4744, Vol. 39, no 7, p. 2633-2642Article, review/survey (Refereed)
    Abstract [en]

    In this critical review, we discuss the history and development of polymer devices wherein manipulation of the electronic conductivity by electrochemical redox processes in a conjugated polymer is used to form new functions. The devices employed are an electrochemical transistor, an electrolyte-gated field-effect transistor and light-emitting electrochemical cells, all of which combine doping/undoping of a conjugated polymer with modification of electronic transport (130 references).

  • 168.
    Müller, Christian
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Ergang
    Chalmers.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Mats R.
    Chalmers.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Influence of Molecular Weight on the Performance of Organic Solar Cells Based on a Fluorene Derivative2010In: ADVANCED FUNCTIONAL MATERIALS, ISSN 1616-301X, Vol. 20, no 13, p. 2124-2131Article in journal (Refereed)
    Abstract [en]

    The performance of organic photovoltaic (OPV) bulk-heterojunction blends comprising a liquid-crystalline fluorene derivative and a small-molecular fullerene is found to increase asymptotically with the degree of polymerization of the former. Similar to various thermodynamic transition temperatures as well as the light absorbance of the fluorene moiety, the photocurrent extracted from OPV devices is found to strongly vary with increasing oligomer size up to a number average molecular weight, M-n approximate to 10 kg mol(-1), but is rendered less chain-length dependent for higher M-n as the fluorene derivative gradually adopts polymeric behavior.

  • 169.
    Cai, Tianqi
    et al.
    Chalmers.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Ergang
    Chalmers.
    Hellstrom, Stefan
    Chalmers.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Xu, Shiai
    East China University of Science and Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Low bandgap polymers synthesized by FeCol(3) oxidative polymerization2010In: SOLAR ENERGY MATERIALS AND SOLAR CELLS, ISSN 0927-0248, Vol. 94, no 7, p. 1275-1281Article in journal (Refereed)
    Abstract [en]

    Four low bandgap polymers, combining an alkyl thiophene donor with benzo[c][1,2,5]thiadiazole, 2,3-diphenylquinoxaline, 2,3-diphenylthieno[3,4-b]pyrazine and 6,7-diphenyl-[1,2,5]thiadiazolo[3,4-g] quinoxaline acceptors in a donor-acceptor-donor architecture, were synthesized via FeCl3 oxidative polymerization. The molecular weights of the polymers were improved by introducing o-dichlor-obenzene (ODCB) as the reaction solvent instead of the commonly used solvent, chloroform. The photophysical, electrochemical and photovoltaic properties of the resulting polymers were investigated and compared. The optical bandgaps of the polymers vary between 1.0 and 1.9 eV, which is promising for solar cells. The devices spin-coated from an ODCB solution of P1DB:[70]PCBM showed a power conversion efficiency of 1.08% with an open-circuit voltage of 0.91 V and a short-circuit current density of 3.36 mA cm(-2) under irradiation from an AM1.5G solar simulator (100 mW cm(-2)).

  • 170.
    Tvingstedt, Kristofer
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Vandewal, Koen
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    On the Dissociation Efficiency of Charge Transfer Excitons and Frenkel Excitons in Organic Solar Cells: A Luminescence Quenching Study2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 49, p. 21824-21832Article in journal (Refereed)
    Abstract [en]

    The field dependence of photocurrent found in many organic solar cells is a significant and detrimental setback for internal quantum efficiency. In this work we study the important contribution to this field dependence due to the dissociation efficiency of the weakly bound interfacial charge transfer (CT) state, crucial for organic bulk heterojunction solar cells. Three different donor polymers and two different acceptors are examined, and their respective dissociation characteristics are evaluated by photoluminescence (PL) quenching, both for Frenkel excitons and for the intermolecular charge transfer excitons. We observe that while the field-dependent photocurrent for pure polymers does correlate well with quenching efficiency, the CT exciton quenching from the blend generally displays a less pronounced correlation with extracted photocurrent. We further note that while the electroluminescence and photoluminescence of the pure polymer are identical, we observe a red shift for the blend electroluminescence. This indicates that lower energetic states, not visible in PL, are available in the blend. The emissive state of the blends probed by PL is therefore proposed to originate from sites that are involved in photocurrent generation to a lesser extent.

  • 171.
    He, Youjun
    et al.
    Chinese Acadamy of Science.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhao, Guangjin
    Chinese Acadamy of Science.
    Min, Jie
    Chinese Acadamy of Science.
    Guo, Xia
    Chinese Acadamy of Science.
    Zhang, Bo
    Chinese Acadamy of Science.
    Zhang, Maojie
    Chinese Acadamy of Science.
    Zhang, Jing
    Chinese Acadamy of Science.
    Li, Yongfang
    Chinese Acadamy of Science.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Poly(4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b ]dithiophene vinylene): Synthesis, Optical and Photovoltaic Properties2010In: JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, ISSN 0887-624X, Vol. 48, no 8, p. 1822-1829Article in journal (Refereed)
    Abstract [en]

    A new benzodithiophene (BDT)-based polymer, poly(4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b]dithiophene vinylene) (PBDTV), was synthesized by Pd-catalyzed Stille-coupling method. The polymer is soluble in common organic solvents and possesses high thermal stability. PBDTV film shows a broad absorption band covering from 350 nm to 618 nm, strong photoluminescence peaked at 545 nm and high hole mobility of 4.84 x 10(-3) cm(2)/Vs. Photovoltaic properties of PBDTV were studied by fabricating the polymer solar cells based on PBDTV as donor and PC70BM as acceptor. With the weight ratio of PBDTV: PC70BM of 1:4 and the active layer thickness of 65 nm, the power conversion efficiency of the device reached 2.63% with V-oc = 0.71 V, I-sc = 6.46 mA/cm(2), and FF = 0.57 under the illumination of AM1.5, 100 mW/cm(2).

  • 172.
    Inganäs, Olle
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Lars Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hellstrom, Stefan
    Chalmers.
    Andersson, Mats R.
    Chalmers.
    Polymer Photovoltaics with Alternating Copolymer/Fullerene Blends and Novel Device Architectures2010In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 22, no 20, p. E100-E116Article in journal (Refereed)
    Abstract [en]

    The synthesis of novel conjugated polymers, designed for the purpose of photovoltaic energy conversion, and their properties in polymer/fullerene materials and photovoltaic devices are reviewed. Two families of main chain polymer donors, based on fluorene or phenylene and donor-acceptor-donor comonomers in alternating copolymers, are used to absorb the high-energy parts of the solar spectrum and to give high photovoltages in combinations with fullerene acceptors in devices. These materials are used in alternative photovoltaic device geometries with enhanced light incoupling to collect larger photocurrents or to enable tandem devices and enhance photovoltage.

  • 173.
    Rizzo, Aurora
    et al.
    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, The Institute of Technology.
    Solin, Niclas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Preparation of Phosphorescent Amyloid-Like Protein Fibrils2010In: CHEMISTRY-A EUROPEAN JOURNAL, ISSN 0947-6539, Vol. 16, no 14, p. 4190-4195Article in journal (Refereed)
    Abstract [en]

    n/a

  • 174.
    Vandewal, Koen
    et al.
    Hasselt University.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Gadisa, Abay
    Hasselt University.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Manca, Jean V
    Hasselt University.
    Relating the open-circuit voltage to interface molecular properties of donor:acceptor bulk heterojunction solar cells2010In: PHYSICAL REVIEW B, ISSN 1098-0121, Vol. 81, no 12, p. 125204-Article in journal (Refereed)
    Abstract [en]

    The open-circuit voltage (V-oc) of polymer:fullerene bulk heterojunction solar cells is determined by the interfacial charge-transfer (CT) states between polymer and fullerene. Fourier-transform photocurrent spectroscopy and electroluminescence spectra of several polymer:fullerene blends are used to extract the relevant interfacial molecular parameters. An analytical expression linking these properties to V-oc is deduced and shown to be valid for photovoltaic devices comprising three commonly used conjugated polymers blended with the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). V-oc is proportional to the energy of the CT states E-CT. The energetic loss q Delta V between E-CT and qV(oc) vanishes when approaching 0 K. It depends linearly on T and logarithmically on illumination intensity. Furthermore q Delta V can be reduced by decreasing the electronic coupling between polymer and fullerene or by reducing the nonradiative recombination rate. For the investigated devices we find a loss q Delta V of similar to 0.6 eV at room temperature and under solar illumination conditions, of which similar to 0.25 eV is due to radiative recombination via the CT state and similar to 0.35 eV is due to nonradiative recombination.

  • 175.
    Sandstrom, Andreas
    et al.
    Umeå University.
    Matyba, Piotr
    Umeå University.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Edman, Ludvig
    Umeå University.
    Separating Ion and Electron Transport: The Bilayer Light-Emitting Electrochemical Cell2010In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, ISSN 0002-7863, Vol. 132, no 19, p. 6646-+Article in journal (Refereed)
    Abstract [en]

    The current generation of polymer light-emitting electrochemical cells (LECs) suffers from insufficient stability during operation. One identified culprit is the active material, which comprises an intimate blend between an ion-conducting electrolyte and an electron-transporting conjugated polymer, as it tends to undergo phase separation during long-term operation and the intimate contact between the ion- and electron-transporting components provokes side reactions. To address these stability issues, we present here a bilayer LEC structure in which the electrolyte is spatially separated from the conjugated polymer. We demonstrate that employing this novel device structure, with its clearly separated ion- and electron-transport paths, leads to distinctly improved LEC performance in the form of decreased turn-on time and improved light emission. We also point out that it will allow for the utilization of combinations of active materials having mutually incompatible solubilities.

  • 176.
    Wang, Ergang
    et al.
    Chalmers.
    Hou, Lintao
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Wang, Zhongqiang
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Hellstrom, Stefan
    Chalmers.
    Mammo, Wendimagegn
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Small Band Gap Polymers Synthesized via a Modified Nitration of 4,7-Dibromo-2,1,3-benzothiadiazole2010In: ORGANIC LETTERS, ISSN 1523-7060, Vol. 12, no 20, p. 4470-4473Article in journal (Refereed)
    Abstract [en]

    The nitration of 4,7-dibromo-2,1,3-benzothiadiazole was modified by using CF3SO3H and HNO3 as the nitrating agent, and the related yield was improved greatly. On the basis of this improvement, two new small band gap polymers, P1TPQ and P3TPQ, were developed. Bulk heterojunction solar cells based on P3TPO and [6,6]-phenyl-C-71-butyric acid methyl ester exhibit interesting results with a power conversion efficiency of 21% and photoresponse up to 1.1 mu m

  • 177.
    Yang, Yi
    et al.
    Chinese Academy of Science.
    Zhang, Jing
    Chinese Academy of Science.
    Zhou, Ye
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Zhao, Guangjin
    Chinese Academy of Science.
    He, Chang
    Chinese Academy of Science.
    Li, Yongfang
    Chinese Academy of Science.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Solution-Processable Organic Molecule with Triphenylamine Core and Two Benzothiadiazole-Thiophene Arms for Photovoltaic Application2010In: JOURNAL OF PHYSICAL CHEMISTRY C, ISSN 1932-7447, Vol. 114, no 8, p. 3701-3706Article in journal (Refereed)
    Abstract [en]

    A new solution-processable biarmed organic molecule With triphenylamine (TPA) core and benzothiadiazole-hexylthiophene (BT-HT) arms, B(TPA-BT-HT), has been synthesized by a Heck reaction, and characterized by UV-vis absorption, cyclic voltammetry, and theoretical calculation. Photovoltaic properties of B(TPA-BT-HT) as light-harvesting and electron-donating material in organic solar cells (OSCs), with [6,6]-phenyl-C61-butyric acid methyl ester (PC60BM) or [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM) as acceptors, were systematically investigated. The performance of the OSCs varied significantly with B(TPA-BT-HT)/fullerene weight ratio, active layer thickness, and solvents Used For spin-coating the active layer. The optimized device with the B(TPA-BT-HT)/PC70BM weight ratio of 1:2 and a thickness of 55 nm with the active layer spin-coated from DCB solution Shows a power conversion efficiency of 1.96% with a short-circuit current density of 5.50 mA/cm(2) and in open-circuit voltage of 0.96 V under (lie illumination of AM 1.5, 100 mw/cm(2).

  • 178.
    Thaning, Elin M
    et al.
    Royal Institute of Technology.
    Asplund, Maria L M
    Royal Institute of Technology.
    Nyberg, Tobias A
    Royal Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    von Hoist, Hans
    Royal Institute of Technology.
    Stability of Poly(3,4-ethylene dioxythiophene) Materials Intended for Implants2010In: JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS, ISSN 1552-4973, Vol. 93B, no 2, p. 407-415Article in journal (Refereed)
    Abstract [en]

    This study presents experiments designed to study the stability of the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT), under simulated physiological conditions using phosphate-buffered saline (PBS) and hydrogen peroxide (H2O2) (0 01M) at 37 degrees C over a 5- to 6-week period Voltage pulsing in PBS was used as an additional test environment The influence of switching the counter ion used in electropolymerization from polystyrene sulphonate (PSS) to heparin was investigated Absorbance spectroscopy and cyclic voltammetry were used to evaluate the material properties Most of the samples in H2O2 lost both electroactivity and optical absorbance within the study period, but PEDOT.PSS was found slightly more stable than PEDOT heparin. Polymers were relatively stable in PBS throughout the study period, with around 80% of electroactivity remaining after 5 weeks, disregarding delamination, which was a significant problem especially for polymer on indium tin oxide substrates Voltage pulsing in PBS did not increase degradation. The counter ion influenced the time course of degradation in Oxidizing agents.

  • 179.
    Hellstrom, Stefan
    et al.
    Chalmers.
    Lindgren, Lars J
    Chalmers.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Synthesis and characterization of three small band gap conjugated polymers for solar cell applications2010In: POLYMER CHEMISTRY, ISSN 1759-9954, Vol. 1, no 8, p. 1272-1280Article in journal (Refereed)
    Abstract [en]

    We report on a new series of small band gap conjugated polymers utilizing donor-acceptor-donor substructures in the polymer backbone to broaden and extend the optical absorption to longer wavelengths. Three polymers were prepared by Suzuki polymerization, using the same donor-acceptor-donor segment but with different comonomers. The goal was to investigate how the optical and electronic properties of the polymers were influenced by the different comonomers. Electrochemical spectroscopy, using square-wave voltammetry, shows that increasing the electron-donating strength of the comonomer will raise the HOMO energy level of the polymer, resulting in a decreased band gap. This result is also manifested by comparing open-circuit voltages from the corresponding laboratory fabricated solar cells. The best performing photovoltaic cell, based on APFO-Green15/[60]PCBM (1 : 4 w/w), reached a J(sc) of 4.2 mA cm(-2), a V-oc of 0.73 V, and a FF of 0.54, giving a PCE of 1.7%.

  • 180.
    Rizzo, Aurora
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. 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.
    Lindgren, Lars J
    Chalmers.
    Andersson, Mats R
    Chalmers.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    White Light with Phosphorescent Protein Fibrils in OLEDs2010In: NANO LETTERS, ISSN 1530-6984, Vol. 10, no 6, p. 2225-2230Article in journal (Refereed)
    Abstract [en]

    Red and yellow phosphorescent insulin amyloid fibrils are used as guest-emitting species within a blue-emitting polyfluorene matrix in light-emitting diodes. The integration of the phosphorescent Ir-complex into the amyloid structures strongly improves the triplet exciton confinement and allows the fabrication of white-emitting device with a very low loading of phosphorescent complex. The overall performances of the devices are improved in comparison with the corresponding bare Ir-complexes. This approach opens a way to explore novel device architectures and to understand the exciton/charge transfer dynamics in phosphorescent light emitting diodes.

  • 181.
    Qin, Ruiping
    et al.
    CAS, Institute Chemistry, Beijing .
    Li, Weiwei
    CAS, Institute Chemistry, Beijing .
    Li, Cuihong
    CAS, Institute Chemistry, Beijing .
    Du, Chun
    CAS, Institute Chemistry, Beijing .
    Veit, Clemens
    Fraunhofer Institute of Solar Energy Systems.
    Schleiermacher, Hans-Frieder
    Fraunhofer Institute of Solar Energy Systems.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Bo, Zhishan
    CAS, Institute Chemistry, Beijing .
    Liu, Zhengping
    Beijing Normal University.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Wuerfel, Uli
    Fraunhofer Institute of Solar Energy Systems.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    A Planar Copolymer for High Efficiency Polymer Solar Cells2009In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, ISSN 0002-7863, Vol. 131, no 41, p. 14612-Article in journal (Refereed)
    Abstract [en]

    An alternating copolymer, poly(2-(5-(5,6-bis(octyloxy)-4-(thiophen-2-yl)benzo[c][1,2,5]thiadiazol-7-yl)thiophen-2-yl)-9-octyt-9H-carbazole) (HXS-1), was designed, synthesized, and used as the donor material for high efficiency polymer solar cells. The close packing of the polymer chains in the solid state was confirmed by XRD. A J(sc) of 9.6 mA/cm(2), a V-proportional to of 0.81 V, an FF of 0.69, and a PCE of 5.4% were achieved with HXS-1 and [6,6]-phenyl C-71-butyric acid methyl ester (PC71BM) as a bulk heterojunction active layer spin-coated from a solvent mixture of 1,2-dichlorobenzene and 1,8-diodooctane (97.5:2.5) under air mass 1.5 global (AM 1.5 G) irradiation of 100 mW/cm(2).

  • 182.
    Krebs, Frederik C
    et al.
    Tech University Denmark, Riso Natl Lab Sustainable Energy, DK-4000 Roskilde, Denmark .
    Gevorgyan, Suren A
    Tech University Denmark, Riso Natl Lab Sustainable Energy, DK-4000 Roskilde, Denmark .
    Gholamkhass, Bobak
    Simon Fraser University, Burnaby, BC V5A 1S6 Canada .
    Holdcroft, Steven
    Simon Fraser University, Burnaby, BC V5A 1S6 Canada .
    Schlenker, Cody
    University So Calif, Department Chemistry, Loker Hydrocarbon Research Institute, Los Angeles, CA 90089 USA Centre Energy Nanosci and Technology, Los Angeles, CA 90089 USA .
    Thompson, Mark E
    University So Calif, Department Chemistry, Loker Hydrocarbon Research Institute, Los Angeles, CA 90089 USA Centre Energy Nanosci and Technology, Los Angeles, CA 90089 USA .
    Thompson, Barry C
    University So Calif, Department Chemistry, Loker Hydrocarbon Research Institute, Los Angeles, CA 90089 USA Centre Energy Nanosci and Technology, Los Angeles, CA 90089 USA .
    Olson, Dana
    NREL, Golden, CO 80401 USA .
    Ginley, David S
    NREL, Golden, CO 80401 USA .
    Shaheen, Sean E
    NREL, Golden, CO 80401 USA University Denver, Department Phys and Astron, Denver, CO 80208 USA .
    Alshareef, Husam N
    University Texas Dallas, Richardson, TX 75080 USA .
    Murphy, John W
    University Texas Dallas, Richardson, TX 75080 USA .
    Youngblood, W Justin
    University N Texas, Department Chemistry, Denton, TX 76201 USA .
    Heston, Nathan C
    University Florida, Department Phys, Centre Macromol Science and Engn, Gainesville, FL 32611 USA .
    Reynolds, John R
    University Florida, Department Chemistry, Centre Macromol Science and Engn, Gainesville, FL 32611 USA .
    Jia, Shijun
    Plextronics Inc, Pittsburgh, PA 15238 USA .
    Laird, Darin
    Plextronics Inc, Pittsburgh, PA 15238 USA .
    Tuladhar, Sachetan M
    University London Imperial Coll Science Technology and Med, Department Phys, Blackett Lab, London SW7 2AZ, England .
    Dane, Justin G A
    University London Imperial Coll Science Technology and Med, Department Phys, Blackett Lab, London SW7 2AZ, England .
    Atienzar, Pedro
    University London Imperial Coll Science Technology and Med, Department Phys, Blackett Lab, London SW7 2AZ, England .
    Nelson, Jenny
    University London Imperial Coll Science Technology and Med, Department Phys, Blackett Lab, London SW7 2AZ, England .
    Kroon, Jan M
    ECN Solar Energy, NL-1755 ZG Petten, Netherlands .
    Wienk, Martijn M
    Eindhoven University Technology, Lab Macromol and Organ Chemistry, NL-5600 MB Eindhoven, Netherlands .
    Janssen, Rene A J
    Eindhoven University Technology, Lab Macromol and Organ Chemistry, NL-5600 MB Eindhoven, Netherlands .
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Lira-Cantu, Monica
    Centre Invest Nanociencia and Nanotecnol, E-08193 Barcelona, Spain .
    de Bettignies, Remi
    CEA INES DRI, Lab Composants Solaires, F-73377 Le Bourget Du lac, France .
    Guillerez, Stephane
    CEA INES DRI, Lab Composants Solaires, F-73377 Le Bourget Du lac, France .
    Aernouts, Tom
    IMEC, PV Department, B-3001 Louvain, Belgium .
    Cheyns, David
    IMEC, PV Department, B-3001 Louvain, Belgium .
    Lutsen, Laurence
    IMEC, IMOMEC, B-3590 Diepenbeek, Belgium .
    Zimmermann, Birger
    Fraunhofer Institute Solare Energiesyst ISE, Department Mat Research and Appl Opt, D-79110 Freiburg, Germany .
    Wuerfel, Uli
    Fraunhofer Institute Solare Energiesyst ISE, Department Mat Research and Appl Opt, D-79110 Freiburg, Germany .
    Niggemann, Michael
    Fraunhofer Institute Solare Energiesyst ISE, Department Mat Research and Appl Opt, D-79110 Freiburg, Germany .
    Schleiermacher, Hans-Frieder
    Fraunhofer Institute Solare Energiesyst ISE, Department Mat Research and Appl Opt, D-79110 Freiburg, Germany .
    Liska, Paul
    Ecole Polytech Fed Lausanne, LPI, Institute Chemistry Science and Engn, Fac Basic Science, CH-1015 Lausanne, Switzerland .
    Graetzel, Michael
    Ecole Polytech Fed Lausanne, LPI, Institute Chemistry Science and Engn, Fac Basic Science, CH-1015 Lausanne, Switzerland .
    Lianos, Panagiotis
    University Patras, Department Engn Science, Patras 26500, Greece .
    Katz, Eugene A
    Ben Gurion University Negev, Jacob Blaustein Institute Desert Research, Department Solar Energy and Environm Phys, IL-84990 Sede Boqer, Israel .
    Lohwasser, Wolfgang
    Alcan Packaging Singen GmbH, D-78221 Singen, Germany .
    Jannon, Bertrand
    Alcan Packaging Singen GmbH, D-78221 Singen, Germany .
    A round robin study of flexible large-area roll-to-roll processed polymer solar cell modules2009In: SOLAR ENERGY MATERIALS AND SOLAR CELLS, ISSN 0927-0248, Vol. 93, no 11, p. 1968-1977Article in journal (Refereed)
    Abstract [en]

    A round robin for the performance of roll-to-roll coated flexible large-area polymer solar-cell modules involving 18 different laboratories in Northern America, Europe and Middle East is presented. The study involved the performance measurement of the devices at one location (Riso DTU) followed by transportation to a participating laboratory for performance measurement and return to the starting location (Riso DTU) for re-measurement of the performance. It was found possible to package polymer solar-cell modules using a flexible plastic barrier material in such a manner that degradation of the devices played a relatively small role in the experiment that has taken place over 4 months. The method of transportation followed both air-mail and surface-mail paths.

  • 183.
    Gedefaw, Desta
    et al.
    Gothenburg University.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Hellstrom, Stefan
    Chalmers Institute of Technology.
    Lindgren, Lars
    Chalmers Institute of Technology.
    Andersson, L.Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Mammo, Wendimagegn
    Chalmers Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers Institute of Technology.
    Alternating copolymers of fluorene and donor-acceptor-donor segments designed for miscibility in bulk heterojunction photovoltaics2009In: JOURNAL OF MATERIALS CHEMISTRY, ISSN 0959-9428, Vol. 19, no 30, p. 5359-5363Article in journal (Refereed)
    Abstract [en]

    A novel copolymer based on alternating fluorene and donor-acceptor-donor segments is reported, together with its photovoltaic properties in blends with fullerene derivatives. The balanced electron and hole mobility of the blends leads to a power-conversion efficiency of 2-3% under solar illumination.

  • 184.
    Inganäs, Olle
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Alternating Polyfluorenes Collect Solar Light in Polymer Photovoltaics2009In: ACCOUNTS OF CHEMICAL RESEARCH, ISSN 0001-4842, Vol. 42, no 11, p. 1731-1739Article in journal (Refereed)
    Abstract [en]

    The effort to improve the energy conversion efficiency of polymer solar cells has led to the design of novel donor polymers. To improve open circuit photovoltages (OCVs) and the spectral coverage of the solar spectrum, researchers have looked for materials with high HOMO values, an easily modified electronic structure, and sufficient electronic transport within the polymers. One advance in design from our laboratories has been the development of a class of alternating polyfluorene copolymers (APFOs), which can be combined with fullerenes to make bulk heterojunction materials for photovoltaic conversion. This Account describes copolymers of fluorene that we designed to expand the range the optical absorption of solar cells to include wavelengths out to 1000 nm. In most cases, we combine these polymers with acceptors from the fullerene family, typically the phenyl C-61 butyric acid methyl ester (PCBM) molecule, to generate solar cell materials. The synthesis of alternating copolymers of fluorene with various donor-acceptor-don or elements provides the opportunity to shift both HOMO and LUMO, which we have followed by electrochemical spectroscopy. Moving the LUMO of the APFOs farther from the vacuum level eventually leads to a situation where the driving force for photo-induced charge transfer from polymer donor to fullerene acceptor goes to zero, resulting in inefficient charge generation. Moving the HOMO level closer to the vacuum level reduces the OCV of devices made from bulk heterojunction blends. As we move the bandgap toward lower energies and increase the overlap of optical absorption with the solar spectrum, both these events eventually occur. In devices based on these APFO/fullerene blends, the performance depends on the OCV, the photocurrent under solar illumination, and the fill factor. The fill factor is influenced by electrical transport and charge generation. Optimizing these parameters requires new solutions to the perennial conflict between optically thin devices, where electrical extraction of charge is not a limitation, and the optically thick devices, where extraction of charge is hampered by trapping and recombination. As a result, we have developed methods to trap light in optically thin devices. When the thin film flexible solar cells are folded, multiple reflection between adjacent solar cells leads to a longer path length for the photon through the devices and considerable improvement of the optical dissipation in the active material. These optical tricks also enable an alternative route to tandem devices, where two different bandgap materials are located on adjacent folds. Thus light not absorbed in one cell is reflected onto the next cell to produce an effective optical series arrangement. Using experiments and simulations of the light trapping effects, we demonstrate power conversion efficiency enhancements of up to a factor of 1.8.

  • 185.
    Andersson, Viktor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Huang, David M
    Chemical Engineering and Materials Science, University of California, Davis, Davis, California 95616, USA.
    Moule, Adam J
    Chemical Engineering and Materials Science, University of California, Davis, Davis, California 95616, USA.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    An optical spacer is no panacea for light collection in organic solar cells2009In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 94, no 4, p. 043302-Article in journal (Refereed)
    Abstract [en]

    The role of an optical spacer layer has been examined by optical simulations of organic solar cells with various bandgaps. The simulations have been performed with the transfer matrix method and the finite element method. The results show that no beneficial effect can be expected by adding an optical spacer to a solar cell with an already optimized active layer thickness.

  • 186.
    Hamedi, Mahiar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Tvinstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Karlsson, Roger H
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Asberg, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Bridging Dimensions in Organic Electronics: Assembly of Electroactive Polymer Nanodevices from Fluids2009In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 9, no 2, p. 631-635Article in journal (Refereed)
    Abstract [en]

    Processing and patterning of electroactive materials from solvents is a hallmark of flexible organic electronics,(1) and commercial applications based on these properties are now emerging. Printing and ink-jetting are today preferred technologies for patterning, but these limit the formation of nanodevices, as they give structures way above the micrometer lateral dimension. There is therefore a great need for cheap, large area patterning of nanodevices and methods for top-down registration of these. Here we demonstrate large area patterning of connected micro/nanolines and nanotransistors from the conducting polymer PEDOT, assembled from fluids. We thereby simultaneously solve problems of large area nanopatterning, and nanoregistration.

  • 187.
    Bjorstrom Svanstrom, Cecilia M
    et al.
    Karlstad University, Department Phys and Elect Engn, S-65188 Karlstad, Sweden .
    Rysz, Jakub
    Jagiellonian University, Institute Phys, PL-30059 Krakow, Poland .
    Bernasik, Andrzej
    AGH University Science and Technology, Fac Phys and Appl Comp Science, PL-30059 Krakow, Poland .
    Budkowski, Andrzej
    Jagiellonian University, Institute Phys, PL-30059 Krakow, Poland .
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers, Department Polymer Technology, S-41296 Gothenburg, Sweden .
    O Magnusson, Kjell
    Karlstad University, Department Phys and Elect Engn, S-65188 Karlstad, Sweden .
    J Benson-Smith, Jessica
    University London Imperial Coll Science Technology and Med, Department Phys, London SW7 2BW, England .
    Nelson, Jenny
    University London Imperial Coll Science Technology and Med, Department Phys, London SW7 2BW, England .
    Moons, Ellen
    Karlstad University, Department Phys and Elect Engn, S-65188 Karlstad, Sweden .
    Device Performance of APFO-3/PCBM Solar Cells with Controlled Morphology2009In: ADVANCED MATERIALS, ISSN 0935-9648, Vol. 21, no 43, p. 4398-+Article in journal (Refereed)
    Abstract [en]

    Polymer/fullerene solar cells with three different device structures: A) diffuse bilayer, B) spontaneously formed multilayer and C) vertically homogeneous thin films, are fabricated. The photocurrent/voltage performance is compared and it is found that the self-stratified structure (B) yields the highest energy conversion efficiency.

  • 188.
    Tvingstedt, Kristofer
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Vandewal, Koen
    Hasselt University.
    Gadisa, Abay
    Hasselt University.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Manca, Jean
    Hasselt University.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Electroluminescence from Charge Transfer States in Polymer Solar Cells2009In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, ISSN 0002-7863, Vol. 131, no 33, p. 11819-11824Article in journal (Refereed)
    Abstract [en]

    In this article we report the weak but omnipresent electroluminescence (EL) from several types of organic polymer:fullerene bulk heterojunction solar cells biased in the forward direction. The light emitted from blends of Some commonly used polymers and the fullerene molecule is significantly different from that of any of the pure materials comprising the blend. The lower energy of the blend EL is found to correlate with both the voltage onset of emission and the open-circuit voltage of the photovoltaic cell under solar illumination. WE., accordingly interpret the emission to originate from interfacial charge transfer state recombination and emphasize EL as a very valuable tool to characterize the charge transfer state present in donor/acceptor organic photovoltaic (OPV) cells.

  • 189.
    Dal Zilio, Simone
    et al.
    National Laboratory of Advanced Technology & NanoScience.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Tormen, Massimo
    National Laboratory of Advanced Technology & NanoScience.
    Fabrication of a light trapping system for organic solar cells2009In: MICROELECTRONIC ENGINEERING, ISSN 0167-9317, Vol. 86, no 4-6, p. 1150-1154Article in journal (Refereed)
    Abstract [en]

    Organic photovoltaic cells (OPV) are among the most promising systems for energy extraction and conversion from renewable energy sources. However, major problem to be solved before industrial production could become economically viable is represented by their still low conversion efficiency. The organic solar cell architectures are presently the result of a compromise between achieving complete light absorption using active layers that are thicker than the optical absorption length and achieving efficient charge collection at the electrodes which is favoured in thinner layers. We present a concept and its experimental demonstration that would solve efficiently the above trade-off problem by making use of a new type of light trapping elements. The simple fabrication scheme, based on a self-aligned UV exposure process, suggests its potential up-scalability to large systems, at low production cost.

  • 190.
    Hamedi, Mahiar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Herlogsson, Lars
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Marcilla, Rebeca
    CIDETEC, Spain.
    Berggren, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Fiber-Embedded Electrolyte-Gated Field-Effect Transistors for e-Textiles2009In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 21, no 5, p. 573-577Article in journal (Refereed)
    Abstract [en]

    Electrolyte-gate organic field-effect transistors embedded at the junction of textile microfibers are demonstrated. The fiber transistor operates below I V and delivers large current densities. The transience of the organic thin-film transistors current and the impedance spectroscopy measurements reveal that the channel is formed in two steps.

  • 191.
    Andersson, Mattias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs , Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    From short to long - Optical and electrical transients in photovoltaic bulk heterojunctions of polyfluorene/fullerenes2009In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 357, no 1-3, p. 120-123Article in journal (Refereed)
    Abstract [en]

    We combine results from transient optical absorption in a bulk heterojunction polymer donor/fullerene acceptor material, obtained in the optical range as well as in the THz range, with results from electrical transients after a short light pulse, to present a unified interpretation of the transport of charge after the very first act of photoinduced charge transfer. We find that the mobility of charges is initially very high, but dramatically reduced with time, to arrive at values three orders of magnitude lower. We show that this can be understood as a consequence of the transport of hot charges by hopping through the density of states, from higher to lower energies.

  • 192.
    Andersson, Viktor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Herland, Anna
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Masich, Sergej
    Karolinska Institutet.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Imaging of the 3D Nanostructure of a Polymer Solar Cell by Electron Tomography2009In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 9, no 2, p. 853-855Article in journal (Refereed)
    Abstract [en]

    Electron tomography has been used for analyzing the active layer in a polymer solar cell, a bulk heterojunction of an alternating copolymer of fluorene and a derivative of fullerene. The method supplies a three-dimensional representation of the morphology of the film, where domains with different scattering properties may be distinguished. The reconstruction shows good contrast between the two phases included in the film and demonstrates that electron tomography is an adequate tool for investigations of the three-dimensional nanostructure of the amorphous materials used in polymer solar cells.

  • 193.
    Zhou, Yinhua
    et al.
    Jilin University.
    Li, Fenghong
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Barrau, Sophie
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tian, Wenjing
    Jilin University.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inverted and transparent polymer solar cells prepared with vacuum-free processing2009In: SOLAR ENERGY MATERIALS AND SOLAR CELLS, ISSN 0927-0248, Vol. 93, no 4, p. 497-500Article in journal (Refereed)
    Abstract [en]

    Inverted transparent polymer solar cells were fabricated by sequentially depositing several organic layers from fluids, on ITO/glass substrates. ITO was used as a cathode to collect electrons. The photovoltage of these diodes can be increased by up to 400 mV by inserting a buffer layer of polyethylene oxide between ITO and the active layers, which results in 4-fold enhancement of power conversion efficiency under the illumination of 100 mW/cm(2) simulated AM1.5 solar light. The enhancement of V., is consistent with the work function change between ITO and ITO/PEO measured by photoelectron spectroscopy. Solar cell production without vacuum processing may lower production costs.

  • 194.
    Karlsson, Roger
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Herland, Anna
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Hamedi, Mahiar
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wigenius, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Åslund, Andreas
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Iron-Catalyzed Polymerization of Alkoxysulfonate-Functionalized 3,4-Ethylenedioxythiophene Gives Water-Soluble Poly(3,4-ethylenedioxythiophene) of High Conductivity2009In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 21, no 9, p. 1815-1821Article in journal (Refereed)
    Abstract [en]

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

  • 195.
    Barrau, Sophie
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Viktor
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Masich, Sergej
    Karolinska Institutet, Stockholm.
    Bijleveld, Johan
    Chalmers University of Technology, Göteborg.
    Andersson, Mats R
    Chalmers University of Technology, Göteborg.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Nanomorphology of Bulk Heterojunction Organic Solar Cells in 2D and 3D Correlated to Photovoltaic Performance2009In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 42, no 13, p. 4646-4650Article in journal (Refereed)
    Abstract [en]

    Control of the nanoscale morphology of the donor-acceptor material blends inorganic solar Cells is critical for optimizing the photovoltaic performances. The influence of intrinsic (acceptor materials) and extrinsic (donor:acceptor weight ratio, substrate, solvent) parameters was investigated, by atomic force microscopy (AFM) and electron tomography (ET), on the nanoscale phase separation of blends of a low-band-gap alternating polyfluorene copolymers (APFO-Green9) with [6,6]-phenyl-C-71-butyric acid methyl ester ([70]PCBM). The photovoltaic performances display an optimal efficiency for the device elaborated with a 1:3 APFO-Green polymer:[70][PCBM weight ratio and spin-coated from chloroform solution. The associated active layer morphology presents small phase-separated domains which is a good balance between as a large interfacial donor-acceptor area and Continuous paths of the donor and acceptor phases to the electrodes.

  • 196.
    Zhou, Yi
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Du, Chunxia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ni, Wei-Xin
    Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics. Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers, Dept Chem & Biol Engn.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Observation of a Charge Transfer State in Low-Bandgap Polymer/Fullerene Blend Systems by Photoluminescence and Electroluminescence Studies2009In: ADVANCED FUNCTIONAL MATERIALS, ISSN 1616-301X, Vol. 19, no 20, p. 3293-3299Article in journal (Refereed)
    Abstract [en]

    The presence of charge transfer states generated by the interaction between the fullerene acceptor PCBM and two alternating copolymers of fluorene with donor-acceptor-donor comonomers are reported; the generation leads to modifications in the polymer bandgap and electronic structure. In one of polymer/fullerene blends, the driving; force for photocurrent generation, i.e., the gap between the lowest unoccupied molecular orbitals of the donor and acceptor, is only 0.1 eV, but photocurrent is generated. It is shown that the presence of a charge transfer state is more important than the driving force. The charge transfer states are visible through new emission peaks in the photoluminescence spectra and through electroluminescence at a forward bias. The photoluminescence can be quenched under reverse bias, and can be directly correlated to the mechanism of photocurrent generation. The excited charge transfer state is easily dissociated into free charge carriers, and is an important intermediate state through which free charge carriers are generated.

  • 197.
    Björk, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Thomsson, Daniel
    Lund University.
    Mirzov, Oleg
    Lund University.
    Andersson, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Scheblykin , Ivan G
    Lund University.
    Oligothiophene Assemblies Defined by DNA Interaction: From Single Chains to Disordered Clusters2009In: SMALL, ISSN 1613-6810 , Vol. 5, no 1, p. 96-103Article in journal (Refereed)
    Abstract [en]

    The organization of conjugated polyelectrolytes (CPEs) interacting with biomolecules sets conditions for the biodetection of biological processes and identity, through the use of optical emission from the CPE. Herein, a well-defined CPE and its binding to DNA is studied. By using dynamic light scattering and circular dichroism spectroscopy, it is shown that the CPE forms a multimolecule ensemble in aqueous solution that is more than doubled it? size when interacting with a small DNA chain, while single chains are evident in ethanol. The related changes in the fluorescence spectra upon polymer aggregation are assigned to oscillator strength redistribution between vibronic transitions in weakly coupled H-aggregates. An enhanced single-molecule spectroscopy technique that allows full control of excitation and emission light polarization is applied to combed and decorated;,DNA chains. It is found that the organization of combed CPE-lambda DNA complexes (when dry on the surface) allows considerable variation of CPE distances and direction relative to the DNA chain. By analysis of the polarization data. energy transfer between the polymer chains in individual complexes is confirmed and their sizes estimated.

  • 198.
    Vandewal, Koen
    et al.
    Hasselt University.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Gadisa, Abay
    Hasselt University.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Manca, Jean V
    Hasselt University.
    On the origin of the open-circuit voltage of polymer-fullerene solar cells2009In: NATURE MATERIALS, ISSN 1476-1122, Vol. 8, no 11, p. 904-909Article in journal (Refereed)
    Abstract [en]

    The increasing amount of research on solution-processable, organic donor-acceptor bulk heterojunction photovoltaic systems, based on blends of conjugated polymers and fullerenes has resulted in devices with an overall power-conversion efficiency of 6%. For the best devices, absorbed photon-to-electron quantum efficiencies approaching 100% have been shown. Besides the produced current, the overall efficiency depends critically on the generated photovoltage. Therefore, understanding and optimization of the open-circuit voltage (V-oc) of organic solar cells is of high importance. Here, we demonstrate that charge-transfer absorption and emission are shown to be related to each other and V-oc in accordance with the assumptions of the detailed balance and quasi-equilibrium theory. We underline the importance of the weak ground-state interaction between the polymer and the fullerene and we confirm that V-oc is determined by the formation of these states. Our work further suggests alternative pathways to improve V-oc of donor-acceptor devices.

  • 199.
    Homa, Bekele
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs , Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Photogenerated charge carrier transport and recombination in polyfluorene/fullerene bilayer and blend photovoltaic devices2009In: ORGANIC ELECTRONICS, ISSN 1566-1199 , Vol. 10, no 3, p. 501-505Article in journal (Refereed)
    Abstract [en]

    Using extraction of photogenerated charge carriers by linearly increasing voltage (photo-CELIV), we investigated two key transport parameters in photovoltaic materials based on the donor APFO-3 and acceptor PCBM: the mobility and lifetime of photogenerated charge carriers, in bilayers of varying geometry and in blends with various acceptors loading. We find that mobility depends strongly on delay time for shorter delay time in all devices. The observed recombination kinetics is found to be monomolecular. The mean lifetime of charge carriers is 2-3 mu s in blends and is slightly greater than 4 mu s in bilayer devices. In addition, the implications of mobility and lifetime values on the collection efficiency of the devices are presented.

  • 200.
    Hellstrom, Stefan
    et al.
    Chalmers.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Structure-property relationships of small bandgap conjugated polymers for solar cells2009In: DALTON TRANSACTIONS, ISSN 1477-9226, Vol. 45, p. 10032-10039Article in journal (Refereed)
    Abstract [en]

    Conjugated polymers as electron donors in solar cells based on donor/acceptor combinations are of great interest, partly due to the possibility of converting solar light with a low materials budget. Six small bandgap polymers with optical bandgap ranging from 1.0-1.9 eV are presented in this paper. All polymers utilize an electron donor-acceptor-donor (DAD) segment in the polymer backbone, creating a partial charge-transfer, to decrease the bandgap. The design, synthesis and the optical characteristics as well as the solar cell characteristics of the polymers are discussed. The positions of the energy levels of the conjugated polymer relative to the electron acceptor are of significant importance and determine not only the driving force for exciton dissociation but also the maximum open-circuit voltage. This work also focuses on investigating the redox behavior of the described conjugated polymers and electron acceptors using square wave voltammetry. Comparing the electrochemical data gives important information of the structure-property relationships of the polymers.

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