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  • 251.
    Müller, Christian
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Jansson, Ronnie
    Department of Anatomy, Physiology and Biochemistry, SLU, Biomedical Centre, Uppsala, Sweden.
    Elfwing, Anders
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Askarieh, Glareh
    Department of Molecular Biology, Uppsala BioCenter, SLU, Biomedical Centre, Uppsala, Sweden .
    Karlsson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. 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.
    Rising, Anna
    Department of Anatomy, Physiology and Biochemistry, SLU, Biomedical Centre, Uppsala, Sweden .
    Johansson, Jan
    Department of Anatomy, Physiology and Biochemistry, SLU, Biomedical Centre, Uppsala, Sweden .
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Hedhammar, My
    Department of Anatomy, Physiology and Biochemistry, SLU, Biomedical Centre, Uppsala, Sweden .
    Functionalisation of recombinant spider silk with conjugated polyelectrolytes2011In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, no 9, p. 2909-2915Article in journal (Refereed)
    Abstract [en]

    Conjugated polyelectrolytes are demonstrated to permit facile staining of recombinant spider silk fibres. We find that the polyelectrolyte concentration and pH of the staining solution as well as the incubation temperature strongly influence the efficiency of this self-assembly process, which appears to be principally mediated through favourable electrostatic interactions. Thus, depending on the choice of staining conditions as well as the polyelectrolyte, electrically conductive or photoluminescent recombinant silk fibres could be produced. In addition, staining of natural Bombyx mori silk is established, which emphasises the versatility of the here advanced approach to functionalise silk-based materials.

  • 252.
    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.

  • 253.
    Nagaraju, D. H.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Rebis, Tomasz
    Poznan University of Tech, Poland .
    Gabrielsson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Elfwing, Anders
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Milczarek, Grzegorz
    Poznan University of Tech, Poland .
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Charge Storage Capacity of Renewable Biopolymer/Conjugated Polymer Interpenetrating Networks Enhanced by Electroactive Dopants2014In: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 4, no 1Article in journal (Refereed)
    Abstract [en]

    Renewable materials are requested for large scale electrical storage, a coming necessity with the growth of intermittent solar and wind renewable electricity generation. Biopolymers are a source of inexpensive materials, in particular through the use of black liquor from paper production, a waste product. Interpenetrating networks of the biopolymer lignosulfonate (Lig) and conjugated polymer polypyrrole (Ppy) are synthesized by galvanostatic polymerization from pyrrole/lignosulfonate mixture in acidic aqueous electrolyte. Methoxy and phenolic functional group present in the non-conducting lignosulfonate are converted to quinone groups. The redox chemistry of quinones is used for charge storage, along with charge storage in polypyrrole. A large variation of the electrochemical activity between lignosulfonates obtained from different sources is observed. The charge storage capacities are significantly enhanced by also including another electroactive dopant, anthraquinone sulfonate (AQS). AQS redox peaks act as an internal reference (standard) to probe the redox electrochemistry of Lig. The synthesized Ppy(Lig) and Ppy(Lig-AQS) electrodes are characterized by cyclic voltammetry, galvanostatic charge-discharge cycling, electrochemical quartz crystal microbalance, and atomic force microscopy.

  • 254.
    Nemec, H.
    et al.
    Nemec, H., Department of Chemical Physics, Lund University, Getingevdgen 60, 222 41 Lund, Sweden.
    Nienhuys, H.-K.
    Institute for Atomic and Molecular Physics, Kruislaan 407, 1098SJ Amsterdam, Netherlands.
    Zhang, Fengling
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Yartsev, A.
    Department of Chemical Physics, Lund University, Getingevdgen 60, 222 41 Lund, Sweden.
    Sundstrom, V.
    Sundström, V., Department of Chemical Physics, Lund University, Getingevdgen 60, 222 41 Lund, Sweden.
    Charge carrier dynamics in alternating polyfluorene copolymer: Fullerene blends probed by terahertz spectroscopy2008In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 112, no 16, p. 6558-6563Article in journal (Refereed)
    Abstract [en]

    Time-resolved terahertz spectroscopy is used for investigation of photoinduced charge carrier dynamics in blends of a polyfluorene copolymer (poly[2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2-thienyl- 2',1',3-benzo-thiadiazole)]) and an electron acceptor ([6,6]-phenyl-C61-butyric acid methyl ester). The transient far-infrared response appears instantaneously after photoexcitation. We show that the transient conductivity spectrum is dominated by two major contributions: response of separated charge carriers and response of coupled polaron pairs. © 2008 American Chemical Society.

  • 255.
    Nemec, Hynek
    et al.
    Lund University.
    Nienhuys, Han-Kwang
    FOM.
    Perzon, Erik
    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.
    Kuzel, Petr
    Acad Sci Czech Republic.
    Sundstrom, Villy
    Lund University.
    Ultrafast conductivity in a low-band-gap polyphenylene and fullerene blend studied by terahertz spectroscopy2009In: PHYSICAL REVIEW B, ISSN 1098-0121, Vol. 79, no 24, p. 245326-Article in journal (Refereed)
    Abstract [en]

    Time-resolved terahertz spectroscopy and Monte Carlo simulations of charge-carrier motion are used to investigate photoinduced transient conductivity in a blend of a low-band-gap polyphenylene copolymer and fullerene derivative. The optical excitation pulse generates free holes delocalized on polymer chains. We show that these holes exhibit a very high initial mobility as their initial excess energy facilitates their transport over defects (potential barriers) on polymer chains. The conductivity then drops down rapidly within 1 ps, and we demonstrate that this decrease occurs essentially by two mechanisms. First, the carriers loose their excess energy and they thus become progressively localized between the on-chain potential barriers-this results in a mobility decay with a rate of (180 fs)(-1). Second, carriers are trapped at defects (potential wells) with a capture rate of (860 fs)(-1). At longer time scales, populations of mobile and trapped holes reach a quasiequilibrium state and further conductivity decrease becomes very slow. .

  • 256.
    Nemec, Hynek
    et al.
    Lund University.
    Nienhuys, Han-Kwang
    FOM Institute for Atomic and Molecular Physics, Amsterdam.
    Perzon, Erik
    Chalmers 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.
    Kuzel, Petr
    Academy of Sciences of the Czech Republic, Prague.
    Sundström, Villy
    Lund University.
    Sub-Picosecond Time-Dependent Mobility in Low-Band-Gap Polyphenylene:Fullerene Blend Probed by Terahertz Spectroscopy2008In: Conference on Lasers and Electro-Optics, 2008 and 2008 Conference on Quantum Electronics and Laser Science. CLEO/QELS 2008, IEEE , 2008, p. 3108-3109Conference paper (Refereed)
    Abstract [en]

    Time-resolved terahertz spectroscopy is used to investigate photoinduced dynamics of charge carriers in a polymer heterojunction. We directly observe instantaneous generation of highly mobile charge carriers followed by a rapid drop in their mobility. (C) 2008 Optical Society of America

  • 257.
    Nilsson, K.Peter R.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, M.R.
    Department of Polymer Technology, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics.
    Conformational transitions in a free amino acid functionalized polythiophene2003In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 135-136, p. 291-292Article in journal (Refereed)
    Abstract [en]

    A chiral, 3-substituted polythiophene with an amino acid function shows pH-dependent visible, emission and circular dichroism spectra in buffered aqueous solution. At pH equal to pi of the amino acid, the backbone adopts a non-planar right-handed helical conformation and the polymer chains are separated from each other. Increasing pH leads to a more planar conformation of the backbone and an aggregation of the polymer chains occurs. A lower pH will also lead to a more planar conformation of the backbone, but aggregation of the polymer chains appears to be absent. © 2003 Elsevier Science B.V. All rights reserved.

  • 258.
    Nilsson, Peter
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, M.R.
    Department of Polymer Technology, Chalmers University of Technology, Göteborg, Sweden.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Conformational transitions of a free amino-acid-functionalized polythiophene induced by different buffer systems2002In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 14, no 42, p. 10011-10020Article in journal (Refereed)
    Abstract [en]

    A chiral, 3-substituted polythiophene with an amino-acid function shows pH-dependent visible, emission and circular dichroism spectra in buffered aqueous solution. At pH equal to the pI of the amino-acid, the backbone adopts a nonplanar right-handed helical conformation and the polymer chains are separated from each other. Increasing pH leads to a more planar conformation of the backbone and an aggregation of the polymer chains occurs. A lower pH will also lead to a more planar conformation of the backbone, but aggregation of the polymer chains appears to be absent. The aggregates are disrupted by increasing ionic strength in alkaline buffer systems, indicating hydrogen bonding is important for aggregation. On the other hand, ions containing an amino group and one or more hydroxyl groups induce a more planar conformation of the polymer backbone.

  • 259.
    Nilsson, Peter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Hammarström, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biochemistry.
    Ahlgren, Fredrik
    Division of Cell Biology Linköpings universitet.
    Herland, Anna
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Schnell, Edrun A
    The Norwegian University of Science and Technology.
    Lindgren, Mikael
    The Norwegian University of Science and Technology.
    Westermark, Gunilla
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Conjugated Polyelectrolytes - Conformation - Sensitive Optical Probes for staining and Characterization of Amyloid Deposits2006In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 7, p. 1096-1104Article in journal (Refereed)
    Abstract [en]

      

  • 260.
    Nilsson, Peter
    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.
    Hammarström, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. 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.
    Conjugated polyelectrolytes: conformation-sensitive optical probes for detection of amyloid fibril formation2005In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 44, no 10, p. 3718-3724Article in journal (Refereed)
    Abstract [en]

    The in vivo deposition of amyloid fibrils is a hallmark of many devastating diseases known as the amyloidoses. Amyloid formation in vitro may also complicate production of proteins in the biotechnology industry. Simple, sensitive, and versatile tools that detect the fibrillar conformation of amyloidogenic proteins are thus of great importance. We have developed a negatively charged conjugated polyelectrolyte that displays different characteristic optical changes, detected visually or by absorption and emission, depending on whether the protein with which it forms a complex is in its native state or amyloid fibril conformation. This simple, rapid, and novel methodology was applied here to two amyloidogenic proteins, insulin and lysozyme, and its validity for detection of their fibrillar conformation was verified by currently used methods such as circular dichroism, transmission electron microscopy, and Congo red absorption.

  • 261.
    Nilsson, Peter
    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.
    Chip and solution detection of DNA hybridization using a luminescent zwitterionic polythiophene derivative2003In: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 2, no 6, p. 419-424Article in journal (Refereed)
    Abstract [en]

    Electronic polymers in aqueous media may offer bioelectronic detection of biospecific interactions. Here we report a fluorometric DNA hybridization detection method based on non-covalent coupling of DNA to a water-soluble zwitterionic polythiophene derivative. Introduction of a single-stranded oligonucleotide will induce a planar polymer and aggregation of the polymer chains, detected as a decrease of the intensity and a red-shift of the fluorescence. On addition of a complementary oligonucleotide, the intensity of the emitted light is increased and blue-shifted. The detection limit of this method is at present ~10−11 moles. The method is highly sequence specific, and a single-nucleotide mismatch can be detected within five minutes without using any denaturation steps. The interaction with DNA and the optical phenomena persists when the polymer is deposited and patterned on a surface. This offers a novel way to create DNA chips without using covalent attachment of the receptor or labelling of the analyte.

  • 262.
    Nilsson, Peter
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Optical emission of a conjugated polyelectrolyte: calcium-induced conformational changes in calmodulin and calmodulin-calcineurin interactions2004In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 37, no 24, p. 9109-9113Article in journal (Refereed)
    Abstract [en]

    Electronic polymers in aqueous media offer bioelectronic detection of biomolecular processes. Here we report fluorometric detection of calcium-induced conformational changes in calmodulin based on noncovalent assembly of calmodulin to a water-soluble zwitterionic polythiophene derivative. Assembly with calmodulin will induce a planar geometry and aggregation of the polymer chains, detected as a decrease of the intensity and a red shift of the fluorescence. Upon addition of Ca2+ the intensity of the emitted light is increased and blue-shifted. The geometrical alteration of the polymer chains can further be utilized for recording of the binding of calcineurin to the calcium-activated POWT−calmodulin complex. This novel methodology, using a conformation-sensitive probe, allows fluorometric detection of conformational changes in biomolecules and protein−protein interactions without any covalent modifications of the biomolecules. The rapid and selective method is based on noncovalent interactions between a zwitterionic polythiophene derivative and the biomolecule of interest. This offers a novel way to create microarrays without using covalent attachment of the receptor or labeling of the analyte.

  • 263.
    Nilsson, Peter
    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.
    Optical sensors based on conjugated polymers2007In: Handbook of conducting polymers (Third Edition) / [ed] Terje A. Skotheim,John Reynolds, CRC Press, 2007, 3, p. -1680Chapter in book (Refereed)
    Abstract [en]

    Learn how recent advances are fueling new possibilities in textiles, optics, electronics, and biomedicine!

    As the field of conjugated, electrically conducting, and electroactive polymers has grown, the Handbook of Conducting Polymershas been there to document and celebrate these changes along the way. Now split into two volumes, this new edition continues to provide the expertise of world-renowned contributors while maintaining the clear format of previous editions as it incorporates the latest developments in both the fundamental science and practical applications of polymers.

    The first volume in the set focuses on the concepts and basic physical aspects needed to understand the behavior and performance of conjugated polymers. The book describes the theories behind π-conjugated materials and electron–lattice dynamics in organic systems. It also details synthesis methods and electrical and physical properties of the entire family of conducting polymers.

    Picking up where the first volume left off, the second volume concentrates on the numerous processing methods for conducting polymers and their integration into various devices and applications. It first examines coating, printing, and spinning methods for complex patterned films and fibers. The book then shows how conducting and semiconducting polymers are applied in many devices, such as light-emitting displays, solar cells, field effect transistors, electrochromic panels, charge storage devices, biosensors, and actuators.

    As the science of conjugated and conducting polymers progresses, further applications will be realized, fueling greater possibilities in textiles, optics, electronics, and biomedicine. This handbook will be there to provide essential information on polymers as well as the most up-to-date developments.

  • 264.
    Nilsson, Peter
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Olsson, Johan
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Enantiomeric substituents determine the chirality of luminescent conjugated polythiophenes2004In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 37, no 17, p. 6316-6321Article in journal (Refereed)
    Abstract [en]

    Chiral isomers of 3-substituted polythiophenes with amino acid functiontionalized side chains are compared. The polymers show pH-dependent absorption, emission, and circular dichroism spectra in buffered aqueous solution. At pH equal to pI of the amino acid, the backbones adopt nonplanar helical conformations, and the polymer chains are separated from each other. Increasing pH leads to more planar conformations of the backbones and an aggregation of the polymer chains occurs. A lower pH will also lead to more planar conformation of the backbones, but aggregation of the polymer chains appears to be absent. The nonplanar to planar transition of the polymer backbone and the separation/aggregation of different polymer chains is not affected by stereochemistry of the zwitterionic side chain. The two isomers have almost identical pH-dependent absorption and emission spectra. However, the chirality of the zwitterionic side chain is reflected in the conformation of the polymer backbone, giving rise to a right-handed and left-handed helical form of polythiophene chains since the induced circular dichroism patterns of the two polymers are mirror images.

  • 265.
    Nilsson, Peter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Olsson, Johan
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Stabo-Eeg, Franz
    The Norwegian University of Scinece and Technology.
    Lindgren, Mikael
    The Norwegian University of Science and Technology.
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Chiral Recognition of a Synthetic Peptide Using Enantiomeric Conjugated Polyelectrolytes and Optical Spectroscopy2005In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 38, p. 6813-6821Article in journal (Refereed)
  • 266.
    Nilsson, Peter
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Rydberg, Johan
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Baltzer, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Organic 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.
    Self-assembly of synthetic peptides control conformation and optical properties of a zwitterionic polythiophene derivative2003In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 100, no 18, p. 10170-10174Article in journal (Refereed)
    Abstract [en]

    The optical transitions of a chiral, three-substituted polythiophene with an amino acid function can be tuned by interactions with synthetic peptides. The addition of a positively charged peptide with a random-coil formation will force the polymer to adopt a nonplanar conformation, and the intensity of the emitted light is increased and blue-shifted. After the addition of a negatively charged peptide with a random-coil conformation, the backbone of the polymer adopts a planar conformation and an aggregation of the polymer chains occurs, seen as a red shift and a decrease of the intensity of the emitted light. By adding the positively charged peptide designed to form a four-helix bundle with the negatively charged peptide, the polymer aggregates are disrupted and the intensity of the emitted light is increased because of separation of the polymer chains. This technique could be used as a platform for making novel sensors and biomolecular switches.

  • 267.
    Nilsson, Peter
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Rydberg, Johan
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Baltzer, Lars
    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.
    Twisting macromolecular chains: self-assembly of a chiral supermolecule from nonchiral polythiophene polyanions and random-coil synthetic peptides2004In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 101, no 31, p. 11197-11202Article in journal (Refereed)
    Abstract [en]

    The self-assembly of a negatively charged conjugated polythiophene derivative and a positively charged synthetic peptide will create a chiral, well ordered supermolecule. This supermolecule has the three-dimensional ordered structure of a biomolecule and the electronic properties of a conjugated polymer. The molecular complex being formed clearly affects the conformation of the polymer backbone. A main-chain chirality, such as a predominantly one-handed helical structure induced by the acid–base complexation between the conjugated polymer and the synthetic peptide, is seen. The alteration of the polymer backbone influences the optical properties of the polymer, seen as changes in the absorption, emission, and Raman spectra of the polymer. The complexation of the polythiophene and the synthetic peptide also induce a change from random-coil to helical structure of the synthetic peptide. The supermolecule described in this article may be used in a wide range of applications such as biomolecular devices, artificial enzymes, and biosensors.

  • 268.
    Nilsson, Peter
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Åslund, Andreas
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry.
    Berg, Ina
    Nyström, Sofie
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biochemistry.
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry.
    Herland, Anna
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics.
    Stabo-Eeg, Frantz
    Lindgren, Mikael
    Westermark, Gunilla
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Lannfelt, Lars
    Nilsson, Lars N G
    Hammarström, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biochemistry.
    Imaging distinct conformational states of amyloid-β fibrils in Alzheimer's disease using novel luminescent probes2007In: ACS Chemical Biology, ISSN 1554-8929, Vol. 2, no 8, p. 553-560Article in journal (Refereed)
    Abstract [en]

    Using luminescent conjugated polyelectrolyte probes (LCPs), we demonstrate the possibility to distinguish amyloid-β 1-42 peptide (Aβ1-42) fibril conformations, by analyzing in vitro generated amyloid fibrils of Aβ1-42 formed under quiescent and agitated conditions. LCPs were then shown to resolve such conformational heterogeneity of amyloid deposits in vivo. A diversity of amyloid deposits depending upon morphology and anatomic location was illustrated with LCPs in frozen ex vivo brain sections from a transgenic mouse model (tg-APPswe) of Alzheimer's disease. Comparative LCP fluorescence showed that compact-core plaques of amyloid β precursor protein transgenic mice were composed of rigid dense amyloid. A more abundant form of amyloid plaque displayed morphology of a compact center with a protruding diffuse exterior. Surprisingly, the compact center of these plaques showed disordered conformations of the fibrils, and the exterior was composed of rigid amyloid protruding from the disordered center. This type of plaque appears to grow from more loosely assembled regions toward solidified amyloid tentacles. This work demonstrates how application of LCPs can prove helpful to monitor aggregate structure of in vivo formed amyloid deposits such as architecture, maturity, and origin.

  • 269.
    Nyberg, Tobias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Jerregard, H
    Linkoping Univ, Appl Phys Lab, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Linkoping Univ, Dept Cellbiol, Inst Biomed & Surg, S-58183 Linkoping, Sweden.
    Polymer hydrogel microelectrodes for neural communication2002In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 4, no 1, p. 43-52Article in journal (Refereed)
    Abstract [en]

    A conducting polymer hydrogel electrode was electrochemically deposited in micromachined via holes and the charge delivery capacity (CDC) was studied. Polymer hydrogel microelectrodes, with a geometric area of 1000 mum(2), and a capacitance of up to 850 nF were fabricated. The impedance of a 1,000 mum(2) polymer hydrogel electrode deposited with 8 muC was measured as low as 8.5 kOmega. We studied neural cell growth on structures to be used as neural interfaces. Directed cell growth was achieved by imposing a topographical structure on the substrate. Due to the interesting mechanical and chemical adaptability of the polymer hydrogel material and its large charge delivery capacity and low impedance we think that it is an interesting material for neural communication.

  • 270.
    Nyberg, Tobias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Zhang, Fengling
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Macromolecular nanoelectronics2002In: Current applied physics, ISSN 1567-1739, E-ISSN 1878-1675, Vol. 2, no 1, p. 27-31Article in journal (Refereed)
    Abstract [en]

    We have explored new organic materials and fabrication methods to fabricate organic photodiodes and light emitting diodes. Grafting of a fullerene derivative to a polythiophene backbone yielded an integrated acceptor-donor polymer that we used as the active material in organic photodiodes. Using a method of soft lithography. soft embossing, we fabricated submicron structures to be used as organic light emitting diodes. Employing a silicone rubber replica (stamp) of an optical diffraction grating we transferred the grating pattern to an organic resist layer by placing the stamp in conformal contact with the resist. The transferred pattern was subsequently used as an etch mask for the processing of the device. The structures were successfully utilized as light emitting diodes and photodiodes, with device characteristics influenced by the imposed structure. (C) 2002 Published by Elsevier Science B.V.

  • 271.
    Nyberg, Tobias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Zhang, Fengling
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Submicrometre bridge electrode arrays for light emitting polymer diodes and photodiodes2002In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 13, no 2, p. 205-211Article in journal (Refereed)
    Abstract [en]

    We have used a method of soft lithography, soft imprinting, to fabricate submicrometre structures to be used as light emitting polymer diodes and photodiodes. Using a silicone rubber replica (stamp) of an optical diffraction grating we transferred the grating pattern to an organic resist layer by placing the stamp in conformal contact with the resist. The transferred pattern was subsequently used as an etch mask for the processing of the device. This cheap and fast process, not limited by optical diffraction, was used to fabricate submicrometre structures over large areas, square millimetres. The structures were successfully utilized as light emitting diodes and photodiodes, with device characteristics influenced by the imposed structure.

  • 272.
    O Reese, Matthew
    et al.
    Nationall Renewable Energy Lab, USA .
    Gevorgyan, Suren A
    Techncal University of Denmark.
    Jorgensen, Mikkel
    Technical University of Denmark.
    Bundgaard, Eva
    Technical University of Denmark.
    Kurtz, Sarah R
    Nationall Renewable Energy Lab, USA .
    Ginley, David S
    Nationall Renewable Energy Lab, USA .
    Olson, Dana C
    Nationall Renewable Energy Lab, USA .
    Lloyd, Matthew T
    Nationall Renewable Energy Lab, USA .
    Moryillo, Pasquale
    ENEA, C.R. Portici, Italy.
    Katz, Eugene A
    Ben Gurion University Negev, Israel.
    Elschner, Andreas
    Heraeus Clevios GmbH, Germany.
    Haillant, Olivier
    Atlas Material Testing Technology GmbH, Germany.
    Currier, Travis R
    Solarmer Energy Inc, USA.
    Shrotriya, Vishal
    Solarmer Energy Inc, USA.
    Hermenau, Martin
    Tech University of Dresden, Germany.
    Riede, Moritz
    Technical University of Dresden.
    Kirov, Kiril R
    Eight 19 Ltd, Cambridge Science Park, Cambridge, UK.
    Trimmel, Gregor
    Graz University of Technology, Austria.
    Rath, Thomas
    Graz University of Technology, Austria.
    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.
    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.
    Lira-Cantu, Monica
    Centre de Investigaciò en Nanociencia i Nanotecnologia, Campus UAB, Edifici ETSE. Spain.
    Laird, Darin
    Plextronics, USA.
    McGuiness, Christine
    Plextronics, USA.
    Gowrisanker, Srinivas (Jimmy)
    Plextronics, USA.
    Pannone, Michael
    Plextronics, USA.
    Xiao, Min
    Plextronics, USA.
    Hauch, Jens
    Konarka Technology GmbH, Germany.
    Steim, Roland
    Konarka Technology GmbH, Germany.
    M DeLongchamp, Dean
    National Institute of Standards and Technology, USA.
    Roesch, Roland
    Ilmenau University of Technology, Germany.
    Hoppe, Harald
    Ilmenau University of Technology, Germany.
    Espinosa, Nieves
    Universidad Politecnica de Cartagena, Spain.
    Urbina, Antonio
    Universidad Politecnica de Cartagena, Spain.
    Yaman-Uzunoglu, Gulsah
    National Metrology Institute , Turkey.
    Bonekamp, Joerg-Bernd
    Soluxx GmbH, Germany.
    J J M van Breemen, Albert
    Holst Centre/TNO, The Netherlands.
    Girotto, Claudio
    IMEC vzw—Organic Photovoltaics, Belgium.
    Voroshazi, Eszter
    IMEC vzw—Organic Photovoltaics, Belgium.
    C Krebs, Frederik
    Techncal University of Denmark.
    Consensus stability testing protocols for organic photovoltaic materials and devices2011In: SOLAR ENERGY MATERIALS AND SOLAR CELLS, ISSN 0927-0248, Vol. 95, no 5, p. 1253-1267Article in journal (Refereed)
    Abstract [en]

    Procedures for testing organic solar cell devices and modules with respect to stability and operational lifetime are described. The descriptions represent a consensus of the discussion and conclusions reached during the first 3 years of the international summit on OPV stability (ISOS). The procedures include directions for shelf life testing, outdoor testing, laboratory weathering testing and thermal cycling testing, as well as guidelines for reporting data. These procedures are not meant to be qualification tests, but rather generally agreed test conditions and practices to allow ready comparison between laboratories and to help improving the reliability of reported values. Failure mechanisms and detailed degradation mechanisms are not covered in this report.

  • 273.
    Ouyang, Liangqi
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Musumeci, Chiara
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jafari, Mohammad Javad
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Imaging the Phase Separation Between PEDOT and Polyelectrolytes During Processing of Highly Conductive PEDOT:PSS Films2015In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 35, p. 19764-19773Article in journal (Refereed)
    Abstract [en]

    Treating PEDOT:PSS (Clevios) with certain additives, such as ethylene glycol (EG), dimethyl sulfoxide (DMSO) and sorbitol, has been shown to increase the conductivity of this material from roughly 1 to nearly 1000 S/cm. Using a slow drying method, we show that the additive induced a separation between free PSS and reorganized PEDOT:PSS complexes in the highly conductive PEDOT:PSS films. Additives (DMSO, DEG, and PEG 400) were included in PEDOT:PSS aqueous dispersions at large volume fractions. The mixtures were slowly dried under room conditions. During drying, the evaporation of water resulted in an additive-rich solvent mixture from which the reorganized PEDOT:PSS complexes aggregated " into a dense film while free PSS remained in the solution. Upon complete drying, PSS formed a transparent rim film around the conducting PEDOT film. The chemical compositions of the two phases were studied using an infrared microscope. This removal of PSS resulted in more compact packing of PEDOT molecules, as confirmed by X-ray diffraction measurements. X-ray photoelectron spectroscopy and atomic force microscope measurements suggested the enrichment of PEDOT on the film surface after PSS separation. Through a simple drying process in an additive-containing dispersion, the conductivity of PEDOT films increased from 0.1 to 200-400 S/cm. Through this method, we confirmed the existence of two phases in additive-treated and highly conductive PEDOT:PSS films. The proper separation between PSS and PEDOT will be of relevance in designing strategies to process high-performance plastic electrodes.

  • 274.
    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.

  • 275.
    Persson, Nils-Krister
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . 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.
    Optical optimization of polyfluorene-fullerene blend photodiodes2005In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 97, no 3, p. 034503-1-034503-8Article in journal (Refereed)
    Abstract [en]

    Blends of polyfluorene-fullerenes are promising materials for polymer-based photovoltaic devices (PPVD). Using spectroscopic ellipsometry we deduce the dielectric function for the blend of the fullerene derivative [6,6]-phenyl-C 61-butyric acid methyl ester (PCBM) and the alternating polyfluorene copolymer, poly [2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1', 3'-benzothiadiazole)] DiO-PFDTBT (4:1 by weight), for the wavelength interval 250-1300 nm. n reaches above 2 and saturates to 1.9 for high wavelengths. Absorption starts at 720 nm (1.72 eV) and reaches a crest around 550 nm (2.25 eV). The spin coating introduces anisotropy in the blend, manifested in birefringence as well as in dichroism. The dielectric function for the blend versus its constituents is not additive. There are indications that the constituents lost their dielectric identity, as screening cannot explain the experimental data. Simulations of optical absorption inside a PPVD are performed for both monochromatic and polychromatic light, using an air mass 1.5 distributed solar irradiation. The model allows calculation of absorbed energies in absolute values in all layers within the device. An optimization is carried out with respect to the layer thicknesses. From a purely optical perspective there is no gain of optical absorbance in including an additional layer of acceptor. Spatially resolved energy dissipation within the device is presented for polychromatic light. Estimates for quantum efficiencies are derived. Experimental and theoretical results for reflectance are compared.

  • 276.
    Persson, Nils-Krister
    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.
    Organic tandem solar cells - modelling and predictions2006In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 90, no 20, p. 3491-3507Article in journal (Refereed)
    Abstract [en]

    Tandem combinations of organic photovoltaic devices are studied from an optical point of view. We unify coherent (wave-based) as well as incoherent (irradiance-based) light addition in our treatment of the incoming and reflected electromagnetic waves, and calculate the spatially resolved absorption profile in the cells. The model allows for any number and any order of thin and thick layers to be analysed. Irradiation is monochromatic or polychromatic, AM 1.5 or AM 1.0, and therefore applicable for solar cell simulation. The optical modelling is unified with electrical models of charge generation and transport in the solar cells. Through this, de-coupling of optical and electrical processes is possible. Moreover, the model allows identification of limiting processes in the devices. The model is applied to a tandem cell with copolymers of polyfluorene combined in bulk heterojunctions with fullerene acceptors, one device for high energy absorption and one for lower, where anodes and cathodes for the cells are semi-transparent metallic polymer layers. It is concluded that these materials do not at present have an electrical performance, which can be enhanced by the tandem cell combination.

  • 277.
    Persson, Nils-Krister
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics.
    Simulations of optical processes in organic photovoltaic devices2005In: Organic Photovoltaics: Mechanisms, Materials and Devices / [ed] Sam-Shajing Sun, Niyazi Serdar Sariciftci, Boca Raton, FL, USA: CRC Press , 2005, 1, p. 107-138Chapter in book (Other academic)
    Abstract [en]

    Recently developed organic photovoltaics (OPVs) show distinct advantages over their inorganic counterparts due to their lighter weight, flexible shape, versatile materials synthesis and device fabrication schemes, and low cost in large-scale industrial production. Although many books currently exist on general concepts of PV and inorganic PV materials and devices, few are available that offer a comprehensive overview of recently fast developing organic and polymeric PV materials and devices.

    Organic Photovoltaics: Mechanisms, Materials, and Devicesfills this gap. The book provides an international perspective on the latest research in this rapidly expanding field with contributions from top experts around the world.  It presents a unified approach comprising three sections: General Overviews; Mechanisms and Modeling; and Materials and Devices. Discussions include sunlight capture, exciton diffusion and dissociation, interface properties, charge recombination and migration, and a variety of currently developing OPV materials/devices. The book also includes two forewords: one by Nobel Laureate Dr. Alan J. Heeger, and the other by Drs. Aloysius Hepp and Sheila Bailey of NASA Glenn Research Center.

    Organic Photovoltaics equips students, researchers, and engineers with knowledge of the mechanisms, materials, devices, and applications of OPVs necessary to develop cheaper, lighter, and cleaner renewable energy throughout the coming decades.

  • 278.
    Persson, Nils-Krister
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Schubert, Mathias
    Universität Leipzig, Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, AG Festkörperoptik und Akustik, Germany.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Optical modelling of a layered photovoltaic device with a polyfluorene derivative/fullerene as the active layer2004In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 83, no 2-3, p. 169-186Article in journal (Refereed)
    Abstract [en]

    Here we report on optical modelling of organic photovoltaic devices having a layered geometry, with polyfluorene-copolymer as the active material and C60 as the acceptor. Thin film theory in a matrix formalism enables analysis of the impact of reflection and interference on the optical electric field. The model allows us to predict an optimal C60 thickness where concern has been taken for light being both polychromatic and distributed according to solar irradiation. Fundamental for light–matter interaction is the dielectric function. We have extracted it for two variants of a new polyfluorene copolymer, PFDTBT, from UV via visible to the nearest infrared, using spectroscopic ellipsometry (SE). n is found to be relatively high with a max-value above 2.1. The process of spin coating induces anisotropy in the polymer film.

  • 279.
    Persson, Nils-Krister
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Sun, Mengtao
    Chemical Physics, Lund University, Lund, Sweden .
    Kjellberg, Pär
    Chemical Physics, Lund University, Lund, Sweden .
    Pullerits, Tänu
    Chemical Physics, Lund University, Lund, Sweden .
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Optical properties of low band gap alternating copolyfluorenes for photovoltaic devices2005In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 123, no 20, p. 204718-Article in journal (Refereed)
    Abstract [en]

    In a joint experimental and theoretical work the optical response and excited-state character of two novel conjugated polymers for photovoltaic applications are studied. The polymers, alternating polyfluorene (APFO) Green 1 and APFO Green 2, are both copolymers of fluorene, thiophene, and electron accepting groups. The band gaps are extended into the red and near infrared with onsets of 780 and 1000 nm, respectively, due to alternating donor and acceptor moieties along the polymer chain. Spectroscopic ellipsometry and subsequent modeling made it possible to extract the dielectric function in the range of 260-1200 nm. Semiempirical quantum chemical calculations (ZINDO) revealed the character of the main electronic transitions in the studied spectral region. The spectral band just above 400 nm was assigned to a delocalized π - π* transition for both polymers. The red band lying at 622 and 767 nm in the two polymers corresponds to an electronic state mainly occupying the acceptor units and having a strong charge-transfer character. We show that the ZINDO transition energies are valuable input to the application of Lorentz oscillators in modeling of the dielectric function of the polymer material.

  • 280.
    Persson, Nils-Krister
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wang, Xiangjun
    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.
    Optical limitations in thin-film low-band-gap polymer/fullerene bulk heterojunction devices2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, no 8, p. 083503-Article in journal (Refereed)
    Abstract [en]

    Photovoltaic devices from the low-band-gap alternating copolymer APFO-Green1, blended with the fullerene derivative BTPF70 as electron acceptor, show a pronounced variation of the external quantum efficiency with varying thickness. Device simulation, based on ellipsometric characterization, reveals that this behavior is to be expected and valid also for most low-band-gap polymers and that it can be explained by optical interference. Requirements for materials suitable for wide spectral coverage in thin-film organic solar cells are delineated. Furthermore, the internal quantum efficiency is calculated to be ≈ 0.4.

  • 281.
    Perzon, Erik
    et al.
    Chalmers University of Technology.
    Wang, Xiangjun
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Admassie, Shimelis
    IFM Linköpings university.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Andersson, Mats R
    Chalmers university of Technology.
    An alternating low band-gap polyfluorene for optoelectronic devices2006In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 47, p. 4261-4268Article in journal (Refereed)
  • 282.
    Perzon, Erik
    et al.
    Chalmers Tekniska Högskola.
    Wang, Xiangjun
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Zhang, Fengling
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Mammo, Wendimagegn
    Chalmers Tekniska Högskola.
    Delgado, Juan Luis
    Universidad de Castilla-La Mancah, Spain.
    de la Cruz, Pilar
    Universidad de Castilla-La Mancha, Spain.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Langa, Fernando
    Universidad de Castilla-La Mancha, Spain.
    Andersson, Mats R
    Chalmers Tekniska Högskola.
    Design, Synthesis and Properties of Low Band Gap Polyfluorenes for Photovoltaic Devices2005In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 154, p. 53-56Article in journal (Refereed)
  • 283.
    Perzon, Erik
    et al.
    Chalmers university of Technology.
    Zhang, Fengling
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Andersson, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Mammo, W.
    Addis Ababa university.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Andersson, M.R.
    Chalmers University of Technology.
    A Conjugated Polymer for Near Infrared Optoelectronic Applications2007In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 19, p. 3308-3311Article in journal (Refereed)
  • 284.
    Pettersson, Fredrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. 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.
    Surface micromachined polymer actuators as valves in PDMS microfluidic system2000In: 1st Annual International, Conference On Microtechnologies in Medicine and Biology. 2000, IEEE , 2000, p. 334-335Conference paper (Refereed)
    Abstract [en]

    To control flows in microfluidic systems there is a need of valves. Desirable properties of such valves are in general low cost, low dead-volume, fast response and low power-consumption. For bioanalytical purposes the requirements also include biocompatibility and ability to function in biological fluids. One way to address these problems is to use surface-fabricated actuators, and then bonding the actuator chip with high aspect-ratio flow-channels in a thick polymer cover. A suitable cover structure can be made in elastomeric poly(dimethylsiloxane) (PDMS) which can be joined to a silicon surface. The active valve structures can be micromuscles, i.e. actuators based on conjugated polymer such as polypyrrole (PPy), which can be electrochemically doped. The reversible doping of PPy forces counterions to flow into or out of the polymer to balance the charge, resulting in a volume change. This volume change can be used in a bilayer actuator, where a metal can serve as constant volume layer as well as electrical contact to the polymer layer changing volume under reversible doping

  • 285.
    Pettersson, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Ghosh, S.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Optical anisotropy in thin films of poly(3,4-ethylenedioxythiophene)- poly(4-styrenesulfonate)2002In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 3, no 3-4, p. 143-148Article in journal (Refereed)
    Abstract [en]

    Anisotropic optical constants spectrum of spin-coated thin films of poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonate) (PEDOT-PSS) from 200 to 1700 nm were determined using variable-angle spectroscopic ellipsometry and polarized intensity transmission data together with absorption spectroscopy. PEDOT-PSS was found to be very anisotropic, uniaxial with the optic axis parallel to the surface normal. The result is in good agreement with results obtained of chemically polymerized PEDOT layers doped with toluenesulfonate. By adding sorbitol to the PEDOT-PSS dispersion before spin-coating, layers with a higher conductivity were obtained. A detailed study was made of the optical response of these layers in comparison to the PEDOT-PSS prepared from dispersions without sorbitol. The optical anisotropy is important to consider when using PEDOT-PSS in optoelectronic devices, such as polymer light-emitting diodes and photovoltaic devices. © 2002 Elsevier Science B.V. All rights reserved.

  • 286.
    Pettersson, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Roman, L.S.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Quantum efficiency of exciton-to-charge generation in organic photovoltaic devices2001In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 89, no 10, p. 5564-5569Article in journal (Refereed)
    Abstract [en]

    We present an analysis of the internal monochromatic quantum efficiency of photovoltaic devices based on polymer and polymer/fullerene thin films. A quantum efficiency of exciton-to-charge generation is defined as the external monochromatic quantum efficiency normalized to the absorption in the active materials of the device. An upper limit of the efficiency can be determined, and results show that much of the light is absorbed in photoactive layers of the device, whereas only a fraction of the generated excitons is converted to charge carriers and can be collected as photocurrent. © 2001 American Institute of Physics.

  • 287.
    Pranculis, Vytenis
    et al.
    Centre Phys Science and Technology, Lithuania .
    Infahsaeng, Yingyot
    Lund University, Sweden .
    Tang, Zheng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Devizis, Andrius
    Centre Phys Science and Technology, Lithuania .
    Vithanage, Dimali A.
    Lund University, Sweden .
    Ponseca, Carlito S. Jr.
    Lund University, Sweden .
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Yartsev, Arkady P.
    Lund University, Sweden .
    Gulbinas, Vidmantas
    Centre Phys Science and Technology, Lithuania .
    Sundstrom, Villy
    Lund University, Sweden .
    Charge Carrier Generation and Transport in Different Stoichiometry APFO3:PC61BM Solar Cells2014In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 136, no 32, p. 11331-11338Article in journal (Refereed)
    Abstract [en]

    In this paper we studied carrier drift dynamics in APFO3:PC61BM solar cells of varied stoichiometry (2:1, 1:1, and 1:4 APFO3:PC61BM) over a wide time range, from subpicoseconds to microseconds with a combination of ultrafast optical electric field probing and conventional transient integrated photocurrent techniques. Carrier drift and extraction dynamics are strongly stoichiometry dependent: the speed of electron or hole drift increases with higher concentration of PC61BM or polymer, respectively. The electron extraction from a sample with 80% PC61BM takes place during hundreds of picoseconds, but slows down to sub-microseconds in a sample with 33% PC61BM. The hole extraction is less stoichiometry dependent: it varies form sub-nanoseconds to tens of nanoseconds when the PC61BM concentration changes from 33% to 80%. The electron extraction rate correlates with the conversion efficiency of solar cells, leading to the conclusion that fast electron motion is essential for efficient charge carrier separation preventing their geminate recombination.

  • 288.
    Qian, Deping
    et al.
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics.
    Liu, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wang, Suhao
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Himmelberger, Scott
    Stanford University, CA 94305 USA.
    Linares, Mathieu
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Chemistry. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Muller, Christian
    Chalmers, Sweden.
    Zaifei, Zaifei
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Salleo, Alberto
    Stanford University, CA 94305 USA.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zou, Yingping
    Central S University, Peoples R China.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Modulating molecular aggregation by facile heteroatom substitution of diketopyrrolopyrrole based small molecules for efficient organic solar cells2015In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, no 48, p. 24349-24357Article in journal (Refereed)
    Abstract [en]

    In conjugated polymers and small molecules of organic solar cells, aggregation induced by intermolecular interactions governs the performance of photovoltaics. However, little attention has been paid to the connection between molecular structure and aggregation within solar cells based on soluble small molecules. Here we demonstrate modulation of intermolecular aggregation of two synthesized molecules through heteroatom substitution to develop an understanding of the role of aggregation in conjugated molecules. Molecule 1 (M1) based on 2-ethylhexyloxy-benzene substituted benzo[1,2-b:4,5-b]dithiophene (BDTP) and diketopyrrolopyrrole (DPP) displays strong aggregation in commonly used organic solvents, which is reduced in molecule 2 (M2) by facile oxygen atom substitution on the BDTP unit confirmed by absorption spectroscopy and optical microscopy, while it successfully maintains molecular planarity and favorable charge transport characteristics. Solar cells based on M2 exhibit more than double the photocurrent of devices based on M1 and yield a power conversion efficiency of 5.5%. A systematic investigation of molecular conformation, optoelectronic properties, molecular packing and crystallinity as well as film morphology reveals structure dependent aggregation responsible for the performance difference between the two conjugated molecules.

  • 289.
    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).

  • 290.
    Rebis, Tomasz
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. Poznan University of Tech, Poland.
    Yang Nilsson, Ting
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hybrid materials from organic electronic conductors and synthetic-lignin models for charge storage applications2016In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 5, p. 1931-1940Article in journal (Refereed)
    Abstract [en]

    Homopolymers and copolymers of the monolignols syringol (S) and guaiacol (G) were prepared as well-defined lignin model compounds. Polymerisation was performed by phenol-formaldehyde condensation, also including the monomer hydroquinone (HQ) to extend the range of redox processes in these synthetic lignins (SLig). The chemical structures of the SLig samples were characterized by C-13 and quantitative P-31 NMR, and the molecular weight was monitored by size exclusion chromatography (SEC). Subsequently, SLig were incorporated into two different electron-conducting matrix - single-wall carbon nanotubes (SWNT) and polypyrrole (PPy), respectively. As a result, the hybrid materials, with a controlled amount of SWNT or with an unknown amount of PPy, were assembled and compared. The charge storage properties in the investigated materials are attributed to contributions from both the double-layer capacitance of the conducting matrix, and the faradaic reactions provided by quinone groups immobilized in the electrodes. The results indicate a considerable improvement of charge capacity, with the synthetic lignins incorporated in the hybrid materials. With a PPy carrying S, G and HQ, better performance is obtained than has previously been obtained with lignin derivatives, showing a maximum capacity of 94 mA h g(-1). Moreover, a low amount of electronic conductor (20% wt of SWNT) is adequate to perform efficient electron communication between redox active quinones and the electrode surface, providing 72 mA h g(-1).

  • 291.
    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

  • 292.
    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.

  • 293. Roman, LS
    et al.
    Arias, AC
    Theander, M
    Andersson, MR
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Photovoltaic devices based on photo induced charge transfer in polythiophene : CN-PPV blends2003In: Brazilian journal of physics, ISSN 0103-9733, E-ISSN 1678-4448, Vol. 33, no 2, p. 376-381Article in journal (Refereed)
    Abstract [en]

    We have investigated the photovoltaic properties of polymer devices based on a blend of two polymers, (poly(3-(2'-methoxy-5'-octylphenyl) thiophene) (POMeOPT) and poly(2,5,2',5'-tetrahexyloxy-7,8'-dicyanodi-p-phenylenevinylene) (CN-PPV), where photo induced charge transfer takes place at the interfaces formed by the interpenetrating network of the donor and the acceptor. The polymer blend films resulting from the spin coating were phase separated and the photo response of the devices depended on the morphology of the segregation. We have studied different blend ratios by photoluminescence quenching, scanning force microscopy and photovoltaic measurements. External quantum efficiencies of 4.5% at 500nm were achieved for the less segregated polymer blend.

  • 294. Roman, L.S.
    et al.
    Berggren, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics.
    Polymer diodes with high rectification1999In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 75, p. 3557-3557Article in journal (Refereed)
  • 295. Roman, L.S.
    et al.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Charge carrier mobility in substituted polythiophene-based diodes2001In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 125, no 3, p. 419-422Article in journal (Refereed)
    Abstract [en]

    We have investigated the transport properties of the semiconducting polymer poly(3-(2'-methoxy-5'-octylphenyl)thiophene) (POMeOPT). We have measured the current-voltage (C-V) characteristics of single polymer layer devices in two regimes contact limited current and bulk-limited current. The passage from one regime to the other was done upon insertion of a conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT-PSS) between the metallic electrode and the semiconducting polymer. With PEDOT-PSS as electrode, the polymer gave space-charge limited current (SCLC) with the mobility dependent on electric field. Fitting the data, we were able to obtain important parameters, such as the zero-field mobility and the characteristic field. We have compared our results with the well-studied polymer poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) in similar experiments earlier reported. © 2001 Elsevier Science B.V. All rights reserved.

  • 296. Roman, LS
    et al.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Granlund, T
    Nyberg, Tobias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Svensson, M
    Andersson, MR
    Hummelen, JC
    Trapping light in polymer photodiodes with soft embossed gratings2000In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 12, no 3, p. 189-+Article in journal (Refereed)
    Abstract [en]

    Increasing the conversion efficiency is very important in photovoltaic devices, as is cheap and simple technology. Here is demonstrated a soft embossing technique for printing a submicrometer grating with an elastomeric mold into an optically active polymer layer in a photovoltaic device (see Figure). The light trapping due to the grating pattern enhances the photoconversion efficiency by more than 25 % at normal light incidence (see also inside front cover).

  • 297.
    Ruseckas, A.
    et al.
    Department of Chemical Physics, Lund University, Box 124, S-221 00 Lund, Sweden.
    Namdas, E.
    Department of Chemical Physics, Lund University, Box 124, S-221 00 Lund, Sweden.
    Theander, M.
    Svensson, M.
    Dept. of Organ. Chem. and Polymer T., Chalmers University of Technology, S-412 96 Göteborg, Sweden.
    Yartsev, A.
    Department of Chemical Physics, Lund University, Box 124, S-221 00 Lund, Sweden.
    Zigmantas, D.
    Department of Chemical Physics, Lund University, Box 124, S-221 00 Lund, Sweden.
    Andersson, M.R.
    Dept. of Organ. Chem. and Polymer T., Chalmers University of Technology, S-412 96 Göteborg, Sweden.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Sundstrom, V.
    Sundström, V., Department of Chemical Physics, Lund University, Box 124, S-221 00 Lund, Sweden.
    Luminescence from inter-chain aggregates in polythiophene films2001In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 119, no 1-3, p. 603-604Article in journal (Refereed)
    Abstract [en]

    We report time-resolved photoluminescence of two polythiophene derivatives with different chain packing. Emission of inter-chain aggregates is distinguished from that of intra-chain singlet excitons. The aggregate luminescence is shifted towards lower energies relative to that of intra-chain exciton by 0.17 eV, and the Huang-Rhys factor of the coupling to the intra-chain C=C vibration is S = 1.5. The excitonic coupling in aggregates is of intermediate strength.

  • 298. Ruseckas, A
    et al.
    Namdas, EB
    Ganguly, T
    Theander, M
    Svensson, M
    Andersson, MR
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Sundstrom, V
    Intra- and interchain luminescence in amorphous and semicrystalline films of phenyl-substituted polythiophene2001In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 105, no 32, p. 7624-7631Article in journal (Refereed)
    Abstract [en]

    We report time-resolved photoluminescence (PL) measurements of spin-cast amorphous films of a regioregular polythiophene derivative poly[3-(4-octylphenyl)thiophene] and of annealed semicrystalline films of the same polymer with an interchain stacking distance of 5 Angstrom. Red-shifted PL appears at long delay times in both pristine and annealed films, which we assign to interchain aggregates populated by excitation energy migration. Aggregate luminescence in annealed films exhibits a pronounced vibronic structure indicating the coupling to a C=C bond stretch with a Huang-Rhys factor S = 2. Two types of aggregates are distinguished in annealed films: in a few picoseconds most excitations are trapped by aggregates with a large energy gap (about 1.83 eV) between the lowest excited singlet state and the ground state. Excitation energy is transferred or the aggregates relax structurally with a time constant of about 200 ps to aggregates with a smaller energy gap (about 1.75 eV). The radiative lifetime of aggregates with smaller energy gap is estimated to be about 35 ns, two times longer than that of aggregates with the larger energy gap. In spin-cast amorphous films, emission from intrachain singlet excitons has a longer lifetime than in annealed films and only high-energy-gap aggregates are populated.

  • 299.
    Ruseckas, A
    et al.
    Lund Univ, Dept Chem Phys, S-22100 Lund, Sweden Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Namdas, EB
    Lund Univ, Dept Chem Phys, S-22100 Lund, Sweden Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Theander, M
    Lund Univ, Dept Chem Phys, S-22100 Lund, Sweden Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Svensson, M
    Yartsev, A
    Lund Univ, Dept Chem Phys, S-22100 Lund, Sweden Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Zigmantas, D
    Lund Univ, Dept Chem Phys, S-22100 Lund, Sweden Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Andersson, MR
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Sundstrom, V
    Lund Univ, Dept Chem Phys, S-22100 Lund, Sweden Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Luminescence quenching by inter-chain aggregates in substituted polythiophenes2001In: Journal of Photochemistry and Photobiology A: Chemistry, ISSN 1010-6030, E-ISSN 1873-2666, Vol. 144, no 1Article in journal (Refereed)
    Abstract [en]

    Time-resolved photo luminescence spectra measured in solid films of two polythiophene derivatives with different chain packing allow to distinguish emission of intra-chain excitations from the luminescence of inter-chain aggregates. Aggregate luminescence is red shifted by about 0.1 eV relative to intra-chain emission and shows vibronic coupling to the C=C bond stretch with the Huang-Phys factor of S approximate to 1.5, which is twice bigger than that of the intra-chain emission. Combining time resolved luminescence data with femtosecond transient absorption, we show that the dynamic quenching of the luminescence in films with dense chain packing is mainly due to excitation energy transfer to aggregates. The radiative lifetime of the lowest excited state of the aggregate with the optical gap of 1.84-1.9 eV is estimated to be about 20 ns. The aggregate contribution to the total luminescence in the polythiophene films with dense chain packing is about 50% and does not change significantly with temperature. (C) 2001 Elsevier Science B.V. All rights reserved.

  • 300.
    Ruseckas, A
    et al.
    Univ Lund, Dept Phys Chem, S-22100 Lund, Sweden Inst Phys, LT-2600 Vilnius, Lithuania Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Polymer Technol, S-41296 Gothenburg, Sweden Univ Trieste, Dipartimento Sci Farmaceut, I-34127 Trieste, Italy.
    Theander, M
    Univ Lund, Dept Phys Chem, S-22100 Lund, Sweden Inst Phys, LT-2600 Vilnius, Lithuania Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Polymer Technol, S-41296 Gothenburg, Sweden Univ Trieste, Dipartimento Sci Farmaceut, I-34127 Trieste, Italy.
    Andersson, MR
    Svensson, M
    Prato, M
    Univ Lund, Dept Phys Chem, S-22100 Lund, Sweden Inst Phys, LT-2600 Vilnius, Lithuania Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Polymer Technol, S-41296 Gothenburg, Sweden Univ Trieste, Dipartimento Sci Farmaceut, I-34127 Trieste, Italy.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Sundstrom, V
    Univ Lund, Dept Phys Chem, S-22100 Lund, Sweden Inst Phys, LT-2600 Vilnius, Lithuania Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Polymer Technol, S-41296 Gothenburg, Sweden Univ Trieste, Dipartimento Sci Farmaceut, I-34127 Trieste, Italy.
    Ultrafast photogeneration of inter-chain charge pairs in polythiophene films2000In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 322, no 1-2, p. 136-142Article in journal (Refereed)
    Abstract [en]

    Photoexcitation dynamics in films of polythiophenes with different side groups were studied by transient absorption spectroscopy using 80 fs pulses. We show that inter-chain charge pairs (CP) are generated with similar to 20% efficiency in a polymer with short inter-chain distance (similar to 4 Angstrom) within 100 fs after photoexcitation. We discuss two mechanisms for inter-chain charge separation: (i) electron or hole transfer from an initially excited intra-chain singlet state or (ii) optical excitation of mixed exciton-charge transfer states, which quickly evolve to inter-chain CPs. (C) 2000 Elsevier Science B.V, All rights reserved.

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