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  • 101.
    Gadisa, Abay
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Wang, X.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Oswald, F.
    Langa, F.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Bipolar transport and infrared light emission in C60 and C70 derivative electron acceptors2006In: Applied Physics Letters, ISSN 0003-6951Article in journal (Refereed)
  • 102.
    Gadisa, Abay
    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.
    Admassie, Shimelis
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Perzon, Erik
    Department of Organic Chemistry and Polymer Technology, Chalmers University of Technology, Göteborg, Sweden.
    Oswald, Frédéric
    Facultad de Ciencias del Medio Ambiente, Universidad de Castilla-La Mancha, Toledo, Spain.
    Langa, Fernando
    Facultad de Ciencias del Medio Ambiente, Universidad de Castilla-La Mancha, Toledo, Spain.
    Andersson, Mats R.
    Department of Organic Chemistry and 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.
    Stoichiometry dependence of charge transport in polymer/methanofullerene and polymer/C70 derivative based solar cells2006In: Organic electronics, ISSN 1566-1199, Vol. 7, no 4, p. 195-204Article in journal (Refereed)
    Abstract [en]

    Charge transport in a near infrared absorbing polyfluorene copolymer (APFO-Green1) and its blends with methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM), and 3′-(3,5-bis-trifluoromethylphenyl)-1′-(4-nitrophenyl)pyrazolino[70]fullerene (BTPF70) is reported. PCBM and BTPF70 are electron acceptor and transporting molecules in polymer based solar cells. The BTPF70 has emerged as a new electron acceptor molecule that provides adequate exciton dissociation when blended with the low band gap polyfluorene copolymer APFO-Green1. Electron transport in both net PCBM and BTPF70 films are subjected to positional and energetic disorder, with the degree of disorder being more pronounced in BTPF70. On the other hand, mixing PCBM with conjugated polymers usually leads to increased hole mobility. We have investigated and compared the acceptor concentration dependence of charge transport in APFO-Green1/PCBM and APFO-Green1/BTPF70 blend films. For better understanding of the charge transport in the heterojunction films, the field and temperature dependence of hole transport in pure APFO-Green1 films has also been studied. It is observed that the behavior of hole mobility in the blend layer is sensitive to the acceptor type. For APFO-Green1/PCBM hole only devices, the hole mobility attains a local maximum at 67 wt.% of PCBM, while on the contrary mixing any amount of BTPF70 with APFO-Green1 results into degradation of hole transport. Electron transport in both blends, however, increases monotonically as a function of acceptor loading.

  • 103.
    Gadisa, Abay
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Wang, Xiangjun
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Perzon, Erik
    Chalmers Tekniska högskola.
    Oswald, Frederic
    Universidad de castilla-La Mancha.
    Langa, F
    Universidad de Castilla -la mancha.
    Andersson, M R
    Chalmers Tekniska Högskola.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Effect of acceptor type on hole transport in polymer/acceptor bulk heterojunction films2006In: European Conference on Hybrid and Organic Cells, ECHOS 06,2006, 2006Conference paper (Other academic)
  • 104.
    Gadisa, Abay
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Sharma, Deepak
    Department of Electrical Engineering, Indian Institute of Technology Kanpur, Kanpur, India.
    Svensson, Mattias
    Department of Organic Chemistry and Polymer Technology, Chalmers University of Technology, Göteborg, Sweden.
    Andersson, Mats R.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Improvements of fill factor in solar cells based on blends of polyfluorene copolymers as electron donors2007In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 5, p. 3126-3131Article in journal (Refereed)
    Abstract [en]

    The photovoltaic characteristics of solar cells based on alternating polyfluorene copolymers, poly(2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)) (APFO-3), and poly(2,7-(9,9-didodecyl-fluorene)-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)) (APFO-4), blended with an electron acceptor fullerene molecule [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), have been investigated and compared. The two copolymers have the same aromatic backbone structure but differ by the length of their alkyl side chain. The overall photovoltaic performance of the solar cells is comparable irrespective of the copolymer used in the active layer. However, the fill factor (FF) values of the devices are strongly affected by the copolymer type. Higher FF values were realized in solar cells with APFO-4 (with longer alkyl side chain)/PCBM bulk heterojunction active layer. On the other hand, devices with blends of APFO-3/APFO-4/PCBM were found to render fill factor values that are intermediate between the values obtained in solar cells with APFO-3/PCBM and APFO-4/PCBM active film. Upon using APFO-3/APFO-4 blends as electron donors, the cell efficiency can be enhanced by about 16% as compared to cells with either APFO-3 or APFO-4. The transport of holes in each polymer obeys the model of hopping transport in disordered media. However, the degree of energetic barrier against hopping was found to be larger in APFO-3. The tuning of the photovoltaic parameters will be discussed based on studies of hole transport in the pure polymer films, and morphology of blend layers. The effect of bipolar transport in PCBM will also be discussed.

  • 105.
    Gao, Feng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Himmelberger, Scott
    Stanford University, CA 94305 USA.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Hanifi, David
    Stanford University, CA 94305 USA.
    Xia, Yuxin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhang, Shaoqing
    Chinese Academic Science, Peoples R China.
    Wang, Jianpu
    Nanjing Technical University, Peoples R China; Nanjing Technical University, Peoples R China.
    Hou, Jianhui
    Chinese Academic Science, Peoples R China.
    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.
    The Effect of Processing Additives on Energetic Disorder in Highly Efficient Organic Photovoltaics: A Case Study on PBDTTT-C-T:PC71BM2015In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 27, no 26, p. 3868-3873Article in journal (Refereed)
    Abstract [en]

    Energetic disorder, an important parameter affecting the performance of organic photovoltaics, is significantly decreased upon the addition of processing additives in a highly efficient benzodithiophene-based copolymer blend (PBDTTT-C-T:PC71BM). Wide-angle and small-angle X-ray scattering measurements suggest that the origin of this reduced energetic disorder is due to increased aggregation and a larger average fullerene domain size together with purer phases.

  • 106.
    Gao, Feng
    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.
    Charge generation in polymer-fullerene bulk-heterojunction solar cells2014In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 38, p. 20291-20304Article in journal (Refereed)
    Abstract [en]

    Charge generation in organic solar cells is a fundamental yet heavily debated issue. This article gives a balanced review of different mechanisms proposed to explain efficient charge generation in polymer-fullerene bulk-heterojunction solar cells. We discuss the effect of charge-transfer states, excess energy, external electric field, temperature, disorder of the materials, and delocalisation of the charge carriers on charge generation. Although a general consensus has not been reached yet, recent findings, based on both steady-state and transient measurements, have significantly advanced our understanding of this process.

  • 107.
    Gao, Feng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology. University of Cambridge, England.
    Tress, Wolfgang
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wang, Jianpu
    University of Cambridge, England; Nanjing Technical University, Peoples R China; Nanjing Technical University, Peoples R China.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Temperature Dependence of Charge Carrier Generation in Organic Photovoltaics2015In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 114, no 12, p. 128701-Article in journal (Refereed)
    Abstract [en]

    The charge generation mechanism in organic photovoltaics is a fundamental yet heavily debated issue. All the generated charges recombine at the open-circuit voltage (VOC), so that investigation of recombined charges at VOC provides a unique approach to understanding charge generation. At low temperatures, we observe a decrease of VOC, which is attributed to reduced charge separation. Comparison between benchmark polymer: fullerene and polymer: polymer blends highlights the critical role of charge delocalization in charge separation and emphasizes the importance of entropy in charge generation.

  • 108.
    Gedefaw, Desta A
    et al.
    Chalmers, Sweden .
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ma, Zaifei
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Genene, Zewdneh
    University of Addis Ababa, Ethiopia .
    Hellstrom, Stefan
    Chalmers, Sweden .
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Mammo, Wendimagegn
    University of Addis Ababa, Ethiopia .
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers, Sweden .
    Conjugated polymers with polar side chains in bulk heterojunction solar cell devices2014In: Polymer international, ISSN 0959-8103, E-ISSN 1097-0126, Vol. 63, no 1, p. 22-30Article in journal (Refereed)
    Abstract [en]

    Two polymers with polar side chains, namely poly[2,7-(9,9-dioctylfluorene)-alt-5,5-(5,8-di-2-thienyl-(2,3-bis(3-(2-(2-methoxyethoxy)ethoxy)phenyl)quinoxaline))] (P1) and poly[2,7-(9,9-bis(2-(2-methoxyethoxy)ethyl)fluorene)-alt-5,5-(5,8-di-2-thienyl-(2,3-bis(3-(2-(2-methoxyethoxy)-ethoxy)phenyl)quinoxaline))] (P2), were synthesized for solar cell application. A series of bulk heterojunction solar cells were systematically fabricated and characterized by varying the electron-acceptor materials, processing solvents and thickness of the active layer. The results show that P1, with a higher molecular weight and good film-forming properties, performed better. The best device showed an open circuit voltage of 0.87 V, a short circuit current of 6.81 mA cm(-2) and a power conversion efficiency of 2.74% with 1:4 polymer:[6,6]-phenyl-C71-butyric acid methyl ester (PCBM[70]) mixture using o-dichlorobenzene (o-DCB) as processing solvent. P2 on the other hand showed a poorer performance with chlorobenzene as processing solvent, but a much improved performance was obtained using o-DCB instead. Thus, an open circuit voltage of 0.80 V, short circuit current of 6.21 mA cm(-2) and an overall power conversion efficiency of 2.22% were recorded for a polymer:PCBM[70] mixing ratio of 1:4. This is presumably due to the improvement of the morphology of the active layer using o-DCB as processing solvent.

  • 109.
    Gedefaw, Desta
    et al.
    Gothenburg University.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Hellstrom, Stefan
    Chalmers Institute of Technology.
    Lindgren, Lars
    Chalmers Institute of Technology.
    Andersson, L.Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Mammo, Wendimagegn
    Chalmers Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers Institute of Technology.
    Alternating copolymers of fluorene and donor-acceptor-donor segments designed for miscibility in bulk heterojunction photovoltaics2009In: JOURNAL OF MATERIALS CHEMISTRY, ISSN 0959-9428, Vol. 19, no 30, p. 5359-5363Article in journal (Refereed)
    Abstract [en]

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

  • 110.
    George, Zandra
    et al.
    Chalmers, Sweden.
    Xia, Yuxin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Sharma, Anirudh
    University of S Australia, Australia.
    Lindqvist, Camilla
    Karlstad University, Sweden.
    Andersson, Gunther
    Flinders University of S Australia, Australia.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Moons, Ellen
    Karlstad University, Sweden.
    Muller, Christian
    Chalmers, Sweden.
    Andersson, Mats R.
    Chalmers, Sweden; University of S Australia, Australia.
    Two-in-one: cathode modification and improved solar cell blend stability through addition of modified fullerenes2016In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 7, p. 2663-2669Article in journal (Refereed)
    Abstract [en]

    The synthesis of dual purpose modified fullerenes with pyridine-as well as amine-functional groups is reported. Addition of these fullerenes to a polymer : fullerene bulk-heterojunction blend based on a thiophene-quinoxaline donor polymer is found to modify the active layer/cathode interface of inverted solar cells (glass/ITO/active layer/MoO3/Al). In particular the open-circuit voltage of devices is increased from 0.1 V to about 0.7 V, which results in a drastic rise in photovoltaic performance with a power conversion efficiency of up to 3%. At the same time, presence of the functionalised fullerene additives prevents the detrimental formation of micrometre-sized fullerene crystals upon annealing at 140 degrees C. As a result, the device performance is retained, which promises significantly increased thermal stability of the bulk-heterojunction blend nanostructure.

  • 111. Ghosh, S.
    et al.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Electrochemical characterization of poly(3,4-ethylene dioxythiophene) based conducting hydrogel networks2000In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 147, no 5, p. 1872-1877Article in journal (Refereed)
    Abstract [en]

    Poly(3,4-ethylene dioxythiophene), a conjugated polymer, doped with excess of polystyrenesulfonate (PSS), has been assembled into a mesoscopic conducting network in the form of a hydrogel. When used as an electrode, the material shows fast electrochemical kinetics as evident from cyclic voltammetry, chronopotentiometry, and impedance measurements. Due to high ionic mobility in the material, the electrochemical process is not limited by ion diffusion in the electrode, as normally is the case for conducting polymers, but by the resistance in the electronically conducting network. This resistance is decreased by growing another conducting polymer, polypyrrole (PPy), inside the hydrogel. Homogeneous deposition of PPy is confirmed by atomic force microscopy. The composite hydrogel also shows larger capacitance, only slightly affecting the kinetics of the electrode. Since the material can be charged and discharged in a very short time, application of such electrodes in high power density supercapacitors has been envisaged.

  • 112. Ghosh, S.
    et al.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Nano-structured conducting polymer network based on PEDOT-PSS2001In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 121, no 1-3, p. 1321-1322Article in journal (Refereed)
    Abstract [en]

    Poly(3,4-ethylenedioxythiophene)-polystyrenesulphonate (PEDOT-PSS) has been crosslinked into network morphology. The morphologies of different crosslinked PEDOT-PSS firms have been characterised by atomic force microscopy (AFM). The crosslinked polymer shows highly efficient and fast redox activity, both in aqueous and non-aqueous media.

  • 113. Ghosh, S.
    et al.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Networks of electron-conducting polymer in matrices of ion-conducting polymers. Applications to fast electrodes2000In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 3, no 5, p. 213-215Article in journal (Refereed)
    Abstract [en]

    Poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (PEDOT-PSS), an electronically conductive electroactive polymer, has been blended with an ion conducting polymer, polyethylene oxide (PEO), to increase the ionic mobility in the material. A substantial increase in the current density is observed in the cyclic voltammogram of the PEDOT-PSS, when the latter is blended with PEO. As supercapacitor electrodes, the blends give much higher energy densities at high power densities compared to the pure PEDOT-PSS. This enhancement of electrochemical properties has been ascribed to both intrinsic ionic conductivity of the PEO, and the swelling of the latter in liquid electrolyte solution, creating space for ion movement.

  • 114. Gillissen, S
    et al.
    Jonforsen, M
    Kesters, E
    Johansson, Tomas
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Theander, M
    Andersson, MR
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Lutsen, L
    Vanderzande, D
    Synthesis and characterization of poly(pyridine vinylene) via the sulfinyl precursor route2001In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 34, no 21, p. 7294-7299Article in journal (Refereed)
    Abstract [en]

    The synthesis and characterization of poly(pyridine vinylene) (PPyV) via the nonionic sulfinyl precursor route is presented. Starting from an unsymmetrical monomer, precursor polymers were prepared in various solvents, which led to polymers with variable molecular weights. The thermal conversion to the conjugated structure, as well as its stability, was studied with different techniques such as FT-IR, UV-vis, TGA, and direct insertion probe mass spectroscopy (DIP-MS). From these results we were able to derive the most suitable conditions to perform the conversion. The fully conjugated PPyV was further characterized with photoluminescence (PL) and cyclic voltammetry (CV) measurements. The PL efficiency was found to be as high as 14%. The CV measurements showed that the polymer can be reduced (n-doped).

  • 115.
    Godovsky, D
    et al.
    Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Gothenburg, Sweden Univ Groningen, Stratingh Inst & Mat Sci Ctr, NL-9747 AG Groningen, Netherlands.
    Chen, LC
    Pettersson, Lars
    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 .
    Andersson, MR
    Hummelen, JC
    Linkoping Univ, IFM, Dept Phys, S-58183 Linkoping, Sweden Chalmers Univ Technol, Gothenburg, Sweden Univ Groningen, Stratingh Inst & Mat Sci Ctr, NL-9747 AG Groningen, Netherlands.
    The use of combinatorial materials development for polymer solar cells2000In: Advanced Materials for Optics and Electronics, ISSN 1057-9257, E-ISSN 1099-0712, Vol. 10, no 2, p. 47-54Article in journal (Refereed)
    Abstract [en]

    Vile use a combinatorial approach to develop molecular plastic solar cells based on soluble fullerene derivatives blended with conjugated polymers. A combinatorial way of sample preparation is well suited to deal with the multitude of possible combinations of the components of such blends. We use high mobility poly(thiophene) and poly(phenylenevinylene) derivatives to be combined with accepters, Gradients of methanofullerene/polymer concentration were formed by diusion of the low molecular weight component in the spin-cast polymer matrix, Likewise the gradients of zinc phthalocyanine/C-60 were prepared by co-evaporation of the two materials from two sources to make a linear array of photodiode devices, Photo- and electrophysical properties, such as absorption, luminescence, short circuit photocurrent and open circuit photovoltage, were measured using a specially designed installation with a resolution of 70-100 mu. Clear evidence was obtained that the photoconversion efficiency increased with the amount of methanofullerene up to very high levels, in the case of methanofullerene/polymer blends, verifying the important role of the acceptor in the photoconversion. By choosing the optimal ratio between C-60 and ZnPc in the evaporated layer it Is possible to obtain high photocurrent in the 600-700 nm range, due to the added contribution from photoinduced electron transfer between the two molecules, Copyright (C) 2000 John Wiley & Sons, Ltd.

  • 116.
    Grage, M.M.-L.
    et al.
    Department of Chemical Physics, Lund University, PO Box 124, S-221 00, Lund, Sweden.
    Pullerits, T.
    Department of Chemical Physics, Lund University, PO Box 124, S-221 00, Lund, Sweden.
    Ruseckas, A.
    Department of Chemical Physics, Lund University, PO Box 124, S-221 00, Lund, Sweden.
    Theander, M.
    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, PO Box 124, S-221 00, Lund, Sweden.
    Conformational disorder of a substituted polythiophene in solution revealed by excitation transfer2001In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 339, no 1-2, p. 96-102Article in journal (Refereed)
    Abstract [en]

    Anisotropy and isotropic transient absorption decays of a polythiophene derivative in dilute solution have been measured and compared to calculated decays on Monte Carlo simulated polymer chains to obtain knowledge about the geometrical conformation of the polymer. The polymer chain conformations are generated by a partially correlated self-avoiding random walk. Excitation migration along the isolated chain is modeled assuming a hopping mechanism. This approach can be used to determine conformational disorder and possible realizations of the polymer chains in solution as well as the trapping time and migration length of the excitation. © 2001 Elsevier Science B.V.

  • 117.
    Granlund, T
    et al.
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Nyberg, Tobias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Roman, LS
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Svensson, M
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Patterning of polymer light-emitting diodes with soft lithography2000In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 12, no 4, p. 269-273Article in journal (Refereed)
  • 118.
    Granlund, T
    et al.
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden.
    Pettersson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Andersson, MR
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Luminescence probing of crystallization in a polymer film2000In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 87, no 12, p. 8549-8556Article in journal (Refereed)
    Abstract [en]

    We report studies of a thin film multilayer stack including a highly emissive substituted polythiophene, poly[3-(2,5-dioctylphenyl)thiophene]. Analysis of the photoluminescence spectra revealed an inhomogeneous polymer film. X-ray diffraction studies attribute the existence of an inhomogeneous film as originating from crystallization of the polymer. We used the interference effect of light to detect the region of crystallization in the film. Photoluminescence and absorption were redshifted upon crystallization and displayed an enhanced vibronic structure. Comparison between calculated and measured photoluminescence shows that the crystallization starts from the top of the film and not from the supporting substrate. (C) 2000 American Institute of Physics. [S0021- 8979(00)08112-3].

  • 119.
    Granlund, T
    et al.
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, S-58183 Linkoping, Sweden.
    Pettersson, Lars
    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 .
    Determination of the emission zone in a single-layer polymer light-emitting diode through optical measurements2001In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 89, no 11, p. 5897-5902Article in journal (Refereed)
    Abstract [en]

    We study the emission zone in a single-layer polymer light-emitting diode. The emission zone is found by studying the angular distribution of the electroluminescence. The emission is modeled by accounting for optical interference. We account for birefringence of the anode layer in our model. The active polymer was, however, found to be isotropic. The anode consists of a single-layer of the conducting polymer complex poly(3,4-ethylenedioxythiophene) and poly(styrene sulfonate) (PEDOT-PSS), with enhanced conductivity. As a cathode we use plain aluminum. By using only PEDOT-PSS we avoid having a thin metal layer or indium-tin-oxide as the anode in the path of the escaping light. The active material is a substituted polythiophene with excellent film forming properties. A comparison between the experimental and calculated angular distribution of light emission from a single-layered polymer light-emitting diode was shown to be in good agreement for the spectral region studied. By assuming a distribution of the emission zone, we deduce the position as well as the width of the zone. (C) 2001 American Institute of Physics.

  • 120.
    Granlund, Thomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Theander, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, M
    Chalmers Tekniska Högskola.
    Ruzeckas, A
    Lunds universitet.
    Sundström, V
    Lunds universitet.
    Björk, G
    KTH.
    Granström, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    A polythiophene microcavity laser1998In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 288, no 5-6, p. 879-884Article in journal (Refereed)
    Abstract [en]

    We report photopumped lasing in a microcavity device with a polythiophene layer as the emitter. These microcavity devices are built by joining two polymer coated dielectric mirrors at elevated temperature. When photopumping the film, a lasing threshold is observed at 120 nJ/cm(2). Comparative studies with fast pump-probe spectroscopy of thin polythiophene films and the same polymer in photopumped lasing studies, indicate that the gain coefficient is 80 +/- 20 cm(-1), and that the exciton concentration is 2 X 10(17) cm(-3) at the lasing transition, well below the exciton-exciton recombination level. (C) 1998 Elsevier Science B.V. All rights reserved.

  • 121.
    Granlund, Thomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Theander, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, Mats
    Chalmers Tekniska Högskola.
    Ruzeckas, A
    Lunds universitet.
    Sundström, V
    Lunds universitet.
    Björk, G
    KTH.
    Granström, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lasing in substituted polythiophene between dielectric mirrors1999In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 102, no 1-3, p. 1038-1041Article in journal (Refereed)
    Abstract [en]

    We report photopumped lasing in a microcavity device with a polythiophene layer as emitter. The microcavity is made of a polymer film between two dielectric Bragg reflecting mirrors (DBR). The:microcavity devices is built by joining two polymer coated DBR mirrors at elevated temperature. When photopumping the film,a lasing threshold is observed at 120 nJ/cm(2). Comparative studies with fast pump-probe spectroscopy of thin polythiophene films, and the same polymer in photopumped lasing studies, indicate that the gain coefficient is 80 +/- 20 cm(2) and that the exciton concentration is 2X10(17) cm(2) at the lasing transition, well below the exciton-exciton recombination level.

  • 122.
    Granström, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Micrometer- and Nanometer-Sized Polymeric Light-Emitting Diodes1995In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 267, no 5203, p. 1479-1481Article in journal (Refereed)
    Abstract [en]

    A method for the fabrication of micrometer- and submicrometer-sized polymeric light-emitting diodes is presented. Such diodes have a variety of applications. Light sources of dimensions around 100 nanometers are required for subwavelength, near-field optical microscopy. Another possible application is patterning on the micrometer and nanometer scale. The diodes have been made in the form of a sandwich structure, with the conductive polymer poly(3,4-ethylene-dioxythiophene) polymerized in the pores of commercially available microfiltration membranes defining the hole-injecting contacts, poly[3-(4-octylphenyl)-2,2-bithiophene] as the light-omitting layer, and a thin film of calcium-aluminum as the electron injector.

  • 123.
    Granström, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Polymeric light-emitting diodes of submicron size - Structures and developments1996In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 76, no 1-3, p. 141-143Article in journal (Refereed)
    Abstract [en]

    Micron- and submicron-sized light-emitting diodes (LEDs) made using conjugated polymers as electroluminescent layers and contact materials are presented. Two different routes to make arrays of such small light sources have been developed. The benefits and drawbacks of the use of the conjugated polymer poly(2,3-ethylene-dioxythiophene) (PEDOT) as hole injector in polymer LEDs are also discussed.

  • 124.
    Granström, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, Mats R.
    Chalmers Tekniska Högskola.
    Hjertberg, T.
    Chalmers Tekniska Högskola.
    Wennerström, O.
    Chalmers Tekniska Högskola.
    Phase separation of conjugated polymers - Tools for new functions in polymer LEDs1997In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 85, no 1-3, p. 1193-1194Article in journal (Refereed)
    Abstract [en]

    Within the single family of substituted poly(thiophenes) it is possible to realize such diverse device designs as voltage controlled colours from polymer LEDs, sub-micron size LEDs, and white light emitters. Many of these features become possible by the use of polymer blends in which one or more poly(thiophenes) are mixed with a matrix polymer (PMMA). The phase structure in these blends can be controlled by stoichiometry and mode of formation. That phase structure can be used to prevent exciton transfer, and to define new colours in polymer LEDs. It also allows us to make anisotropic conductors suitable for contacting optical devices.

  • 125.
    Granström, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Pede, Danilo
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, Mats R.
    Chalmers Tekniska Högskola.
    Hjertberg, T.
    Chalmers Tekniska Högskola.
    Wennerström, O.
    Chalmers Tekniska Högskola.
    Self organizing polymer films - a route to novel electronic devices based on conjugated polymers1997In: Supramolecular science, ISSN 0968-5677, E-ISSN 1873-4146, Vol. 4, no 1-2, p. 27-34Article in journal (Refereed)
    Abstract [en]

    Polymer blends are often used in polymer light emitting diodes as a tool to increase the efficiency of the devices. In this report, we show the necessity to take the phase separation properties of such blends into account, as the miscibility of the involved polymers drastically affects the resulting film structure. By using phase separated polymer blends involving conjugated poly(thiophenes) and different nonconjugated polymers as matrices, different types of applications, such as light emitting diodes with improved voltage control of emitted colour, sub-micron size LEDs and anisotropic conductors are demonstrated. (C) 1997 Elsevier Science Ltd. All rights reserved.

  • 126.
    Hamedi, Mahiar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Elfwing, Anders
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Gabrielsson, Roger H
    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.
    Electronic Polymers and DNA Self-assembled in Nanowire Transistors2013In: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 9, no 3, p. 363-368Article in journal (Refereed)
    Abstract [en]

    In this study the fully acidic form of PEDOT-S was used for the purpose of self-assembly onto DNA. We have previously shown that PEDOT-S is a short polymer that is self-doped with !1/3 of the sulfonate side groups acting as the self-doping sites (see supporting info.). The remaining sulfonate groups contribute to a net anionic charge, and a water-soluble polymer, with an intrinsic bulk conductivity of around 30 S/cm. It has been shown that PEDOT-S can bind to oppositely charged cationic amyloid protein structures in water and form conducting nano fibrillar networks, and it has also been shown to form hybrid structures with synthetic peptides, and gold nanoparticles.

  • 127.
    Hamedi, Mahiar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Forchheimer, Robert
    Linköping University, Department of Electrical Engineering, Image Coding. 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.
    Towards woven logic from organic electronic fibres2007In: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 6, p. 357-362Article in journal (Refereed)
    Abstract [en]

    The use of organic polymers for electronic functions is mainly motivated by the low-end applications, where low cost rather than advanced performance is a driving force. Materials and processing methods must allow for cheap production. Printing of electronics using inkjets1 or classical printing methods has considerable potential to deliver this. Another technology that has been around for millennia is weaving using fibres. Integration of electronic functions within fabrics, with production methods fully compatible with textiles, is therefore of current interest, to enhance performance and extend functions of textiles2. Standard polymer field-effect transistors require well defined insulator thickness and high voltage3, so they have limited suitability for electronic textiles. Here we report a novel approach through the construction of wire electrochemical transistor (WECT) devices, and show that textile monofilaments with 10–100 µm diameters can be coated with continuous thin films of the conducting polythiophene poly(3,4-ethylenedioxythiophene), and used to create micro-scale WECTs on single fibres. We also demonstrate inverters and multiplexers for digital logic. This opens an avenue for three-dimensional polymer micro-electronics, where large-scale circuits can be designed and integrated directly into the three-dimensional structure of woven fibres.

  • 128.
    Hamedi, Mahiar
    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.
    Karlsson, Roger H
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Electrochemical Devices Made from Conducting Nanowire Networks Self-Assembled from Amyloid Fibrils and Alkoxysulfonate PEDOT2008In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, no 6, p. 1736-1740Article in journal (Refereed)
    Abstract [en]

    Proteins offer an almost infinite number of functions and geometries for building nanostructures. Here we have focused on amyloid fibrillar proteins as a nanowire template and shown that these fibrils can be coated with the highly conducting polymer alkoxysulfonate PEDOT through molecular self-assembly in water. Transmission electron microscopy and atomic force microscopy show that the coated fibers have a diameter around 15 nm and a length/thickness aspect ratio >1:1000 . We have further shown that networks of the conducting nanowires are electrically and electrochemically active by constructing fully functional electrochemical transistors with nanowire networks, operating at low voltages between 0 and 0.5 V.

  • 129.
    Hamedi, Mahiar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Herlogsson, Lars
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Marcilla, Rebeca
    CIDETEC, Spain.
    Berggren, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Fiber-Embedded Electrolyte-Gated Field-Effect Transistors for e-Textiles2009In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 21, no 5, p. 573-577Article in journal (Refereed)
    Abstract [en]

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

  • 130.
    Hamedi, Mahiar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Tvinstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Karlsson, Roger H
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Asberg, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Bridging Dimensions in Organic Electronics: Assembly of Electroactive Polymer Nanodevices from Fluids2009In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 9, no 2, p. 631-635Article in journal (Refereed)
    Abstract [en]

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

  • 131.
    He, Youjun
    et al.
    Chinese Acadamy of Science.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhao, Guangjin
    Chinese Acadamy of Science.
    Min, Jie
    Chinese Acadamy of Science.
    Guo, Xia
    Chinese Acadamy of Science.
    Zhang, Bo
    Chinese Acadamy of Science.
    Zhang, Maojie
    Chinese Acadamy of Science.
    Zhang, Jing
    Chinese Acadamy of Science.
    Li, Yongfang
    Chinese Acadamy of Science.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Poly(4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b ]dithiophene vinylene): Synthesis, Optical and Photovoltaic Properties2010In: JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, ISSN 0887-624X, Vol. 48, no 8, p. 1822-1829Article in journal (Refereed)
    Abstract [en]

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

  • 132.
    Hellstrom, Stefan
    et al.
    Chalmers.
    Cai, Tianqi
    Chalmers.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Influence of side chains on electrochromic properties of green donor-acceptor-donor polymers2011In: ELECTROCHIMICA ACTA, ISSN 0013-4686, Vol. 56, no 10, p. 3454-3459Article in journal (Refereed)
    Abstract [en]

    Three solution processable cathodically coloring green electrochromic polymers, based on 2,3-diphenyl-5,7-di(thiophen-2-yl)thieno[3,4-b]pyrazine, have been synthesized by oxidative FeCl3 polymerization. The polymers were designed with solubilizing alkyl and oligoethylene oxide side chains to achieve solubility and processability. All three polymers have a small electrochemical bandgap (1.8-1.9 eV) and low oxidation potentials. Spectroelectrochemical studies of polymer films on ITO reveal that the alkyl side chains in head-to-head position on the polymer backbone promote a defined high-energy absorption peak and suppress tailing of charge-carrier absorption into the visible region. Kinetic studies, based on transmission measurements applying a square-wave potential between reduced and oxidized states, show that the polymer with exclusively oligoethylene oxide side chains (P3) had the fastest response times, monitored at the low-energy absorption maxima. The best performing polymer (P1) showed a good optical contrast in the visible region with a Delta T of 26% at 700 nm. An initial test of the electrochemical stability showed that the oligoethylene oxide containing polymers had superior stability over 500 full switches.

  • 133.
    Hellstrom, Stefan
    et al.
    Chalmers.
    Lindgren, Lars J
    Chalmers.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Synthesis and characterization of three small band gap conjugated polymers for solar cell applications2010In: POLYMER CHEMISTRY, ISSN 1759-9954, Vol. 1, no 8, p. 1272-1280Article in journal (Refereed)
    Abstract [en]

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

  • 134.
    Hellstrom, Stefan
    et al.
    Chalmers.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers.
    Structure-property relationships of small bandgap conjugated polymers for solar cells2009In: DALTON TRANSACTIONS, ISSN 1477-9226, Vol. 45, p. 10032-10039Article in journal (Refereed)
    Abstract [en]

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

  • 135.
    Henriksson, Patrik
    et al.
    Chalmers, Sweden.
    Lindqvist, Camilla
    Chalmers, Sweden.
    Abdisa, Bedasa
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. University of Addis Ababa, Ethiopia.
    Wang, Ergang
    Chalmers, Sweden.
    George, Zandra
    Chalmers, Sweden.
    Kroon, Renee
    Chalmers, Sweden.
    Muller, Christian
    Chalmers, Sweden.
    Yohannes, Teketel
    University of Addis Ababa, Ethiopia.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Mats R.
    Chalmers, Sweden; University of S Australia, Australia.
    Stability study of quinoxaline and pyrido pyrazine based co-polymers for solar cell applications2014In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 130, p. 138-143Article in journal (Refereed)
    Abstract [en]

    We present two co-polymer families; one based on a thiophene-quinoxaline unit and one on a thiophenepyrido pyrazine unit. Co-polymerization of these monomers with thiophene-hexylthiophene was performed to create polymers with an optical absorption that fully covers the visible part of the solar spectrum with the aim to enhance the solar cell performances of these polymers. We have also studied how increasing the fraction of thiophene-hexylthiophene affects the photo-oxidative stability of these polymers. Thiophene-pyrido pyrazine solar cells displayed increased device efficiency upon addition of the thiophene-hexylthiophene and, in addition, the stability is retained upon inclusion of these units. In contrast, we found that for the thiophene-quinoxaline based co-polymer, both device efficiency and stability decreased with increasing thiophene-hexylthiophene fraction. Moreover, our results indicate that the photo-oxidative stability of the thiophene-quinoxaline co-polymer is independent of the polymer molecular weight as well as of the film thickness.

  • 136.
    Herland, Anna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Björk, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Hania, P. Ralph
    Department of Chemical Physics, University of Lund, Lund, Sweden.
    Scheblykin, Ivan G.
    Department of Chemical Physics, University of Lund, Lund, Sweden.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Alignment of a conjugated polymer onto amyloid-like protein fibrils2007In: Small, ISSN 1613-6810, Vol. 3, no 2, p. 318-325Article in journal (Refereed)
    Abstract [en]

    The amyloid-like fibril is a biomolecular nanowire template of very high stability. Here we describe the coordination of a conjugated polyelectrolyte, poly(thiophene acetic acid) (PTAA), to bovine insulin fibrils with widths of <10 nm and lengths of up to more than 10 m. Fibrils complexed with PTAA are aligned on surfaces through molecular combing and transfer printing. Single-molecule spectroscopy techniques are applied to chart spectral variation in the emission of these wires. When these results are combined with analysis of the polarization of the emitted light, we can conclude that the polymer chains are preferentially aligned along the fibrillar axis.

  • 137.
    Herland, Anna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Björk, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Nilsson, K. Peter R.
    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.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry . Linköping University, The Institute of Technology.
    Electroactive luminescent self-assembled bio-organic nanowires: Integration of semiconducting oligoelectrolytes within amyloidogenic proteins2005In: Advanced Materials, ISSN 0935-9648, Vol. 17, no 12, p. 1466-1471Article in journal (Refereed)
  • 138.
    Herland, Anna
    et al.
    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 .
    Conjugated polymers as optical probes for protein interactions and protein conformations2007In: Macromolecular rapid communications, ISSN 1022-1336, E-ISSN 1521-3927, Vol. 28, no 17, p. 1703-1713Article in journal (Refereed)
    Abstract [en]

    There is a need for highly sensitive, multi-parallel protein sensors within diagnostics and proteomic research. Conjugated polymers (CPs) have been demonstrated as highly sensitive optical probes for protein biosensing. Compared to small molecules, the polymeric probe has the possibility of multiple interactions and a collective response, which enhances the sensor signal. The optical output is colorimetric or, more sensitive, fluorescence based, including Förster energy transfer and changes in the emission wavelengths and/or intensity. Using CPs, many interesting protein detection events have been demonstrated, e.g., protein interactions, enzymatic activity, amyloid fibril formation, and detection by aptamers. CPs have also been successfully used to stain bacterial, cellular, and tissue samples. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.

  • 139.
    Herland, Anna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Nilsson, K. Peter R.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Olsson, Johan D. M.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hammarström, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Konradsson, Peter
    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.
    Synthesis of a regioregular zwitterionic conjugated oligoelectrolyte, usable as an optical probe for detection of amyloid fibril formation at acidic pH2005In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 127, no 7, p. 2317-2323Article in journal (Refereed)
    Abstract [en]

    Changes of the optical properties of conjugated polyelectrolytes have been utilized to monitor noncovalent interactions between biomolecules and the conjugated polyelectrolytes in sensor applications. A regioregular, zwitterionic conjugated oligoelectrolyte was synthesized in order to create a probe with a defined set of optical properties and hereby facilitate interpretation of biomolecule−oligoelectrolyte interactions. The synthesized oligoelectrolyte was used at acidic pH as a novel optical probe to detect amyloid fibril formation of bovine insulin and chicken lysozyme. Interaction of the probe with formed amyloid fibrils results in changes of the geometry and the electronic structure of the oligoelectrolyte chains, which were monitored with absorption and emission spectroscopy.

  • 140.
    Herland, Anna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Thomsson, Daniel
    University of Lund.
    Mirzov, Oleg
    University of Lund.
    Scheblykin, Ivan G.
    University of Lund.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Decoration of amyloid fibrils with luminescent conjugated polymers2008In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 18, no 1, p. 126-132Article in journal (Refereed)
    Abstract [en]

    In this work we report the coating of a biological template with a polar, but uncharged, luminescent conjugated polymer, soluble in organic solvents but not in water, to produce a nanowire. Amyloid fibrils from bovine insulin were decorated with an alternating polyfluorene derivative. Decorated fibrils were partially aligned on hydrophobic surfaces as separate and bundled fibrils, by means of molecular combing. The single molecule spectroscopy technique utilizing excitation by rotating linearly polarized light and fluorescence detection through a rotating polarizer showed a high degree of anisotropy of the polymer chains on the individual fibrils. The high degree of polarization indicated highly oriented polymer chains with the preferential orientation of the polymer backbone along the fibrils. The anisotropy ratios are comparable with those of well-oriented polymer chains in films. © The Royal Society of Chemistry.

  • 141.
    Hevekerl, Heike
    et al.
    Royal Institute Technology, Sweden .
    Wigenius, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Persson, Gustav
    Royal Institute Technology, Sweden .
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Widengren, Jerker
    Royal Institute Technology, Sweden .
    Dark States in Ionic Oligothiophene Bioprobes-Evidence from Fluorescence Correlation Spectroscopy and Dynamic Light Scattering2014In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 118, no 22, p. 5924-5933Article in journal (Refereed)
    Abstract [en]

    Luminescent conjugated polyelectrolytes (LCPs) can upon interaction with biological macromolecules change their luminescent properties, and thereby serve as conformation- and interaction-sensitive biomolecular probes. However, to exploit this in a more quantitative manner, there is a need to better understand the photophysical processes involved. We report studies of the conjugated pentameric oligothiophene, derivative p-FTAA, which changes optical properties with different p-FTAA concentrations in aqueous buffers, and in a pH and oxygen saturation dependent manner. Using dynamic light scattering, luminescence spectroscopy and fluorescence correlation spectroscopy, we find evidence for a monomer dimer equilibrium, for the formation of large clusters of p-FTAA in aqueous environment, and can couple aggregation to changed emission properties of oligothiophenes. In addition, we observe the presence of at least two dark transient states, one presumably being a triplet state. Oxygen was found to statically quench the p-FTAA fluorescence but also to promote molecular fluorescence by quenching dark transient states of the p-FTAA molecules. Taken together, this study provides knowledge of fluorescence and photophysical features essential for applying p-FTAA and other oligothiophene derivatives for diagnostic purposes, including detection and staining of amyloid aggregates.

  • 142.
    Homa, Bekele
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs , Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Photogenerated charge carrier transport and recombination in polyfluorene/fullerene bilayer and blend photovoltaic devices2009In: ORGANIC ELECTRONICS, ISSN 1566-1199 , Vol. 10, no 3, p. 501-505Article in journal (Refereed)
    Abstract [en]

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

  • 143.
    Hou, Jianhui
    et al.
    Chinese Acad Sci, Peoples R China.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Friend, Richard H.
    Cavendish Lab, England.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Organic solar cells based on non-fullerene acceptors2018In: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 17, no 2, p. 119-128Article, review/survey (Refereed)
    Abstract [en]

    Organic solar cells (OSCs) have been dominated by donor: acceptor blends based on fullerene acceptors for over two decades. This situation has changed recently, with non-fullerene (NF) OSCs developing very quickly. The power conversion efficiencies of NF OSCs have now reached a value of over 13%, which is higher than the best fullerene-based OSCs. NF acceptors show great tunability in absorption spectra and electron energy levels, providing a wide range of new opportunities. The coexistence of low voltage losses and high current generation indicates that new regimes of device physics and photophysics are reached in these systems. This Review highlights these opportunities made possible by NF acceptors, and also discuss the challenges facing the development of NF OSCs for practical applications.

  • 144.
    Hou, Lintao
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wang, Ergang
    Chalmers.
    Bergqvist, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Viktor
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Zhongqiang
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Müller, Christian
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Campoy-Quiles, Mariano
    Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Esfera UAB, Bellaterra, Spain.
    R Andersson, Mats
    Materials and Surface Chemistry/Polymer Technology, Chalmers University of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Lateral Phase Separation Gradients in Spin-Coated Thin Films of High-Performance Polymer: Fullerene Photovoltaic Blends2011In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 21, no 16, p. 3169-3175Article in journal (Refereed)
    Abstract [en]

    In this study, it is demonstrated that a finer nanostructure produced under a rapid rate of solvent removal significantly improves charge separation in a high-performance polymer: fullerene bulk-heterojunction blend. During spin-coating, variations in solvent evaporation rate give rise to lateral phase separation gradients with the degree of coarseness decreasing away from the center of rotation. As a result, across spin-coated thin films the photocurrent at the first interference maximum varies as much as 25%, which is much larger than any optical effect. This is investigated by combining information on the surface morphology of the active layer imaged by atomic force microscopy, the 3D nanostructure imaged by electron tomography, film formation during the spin coating process imaged by optical interference and photocurrent generation distribution in devices imaged by a scanning light pulse technique. The observation that the nanostructure of organic photovoltaic blends can strongly vary across spin-coated thin films will aid the design of solvent mixtures suitable for high molecular-weight polymers and of coating techniques amenable to large area processing.

  • 145.
    Idla, K.
    et al.
    Laboratory of Physical Chemistry, Tallinn Tech. Univ., Ehitajate T., Tallinn, Estonia.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Strandberg, M.
    Edison Centre, Pikk 39, 10133, Tallinn, Estonia.
    Good adhesion between chemically oxidized titanium and electrochemically deposited polypyrrole2000In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 45, no 13, p. 2121-2130Article in journal (Refereed)
    Abstract [en]

    A method for producing extremely adhesive polypyrrole (Ppy) films is described. The electrochemical synthesis of Ppy on thin chemically pre-oxidized Ti layers produces a mechanically strong, shiny polymer film with extremely good adhesion. Adhesion of Ppy films on Ti metal without chemical pre-oxidation is very weak. Two multilayer systems are described with Ppy as an electrochemically active layer, chemically oxidized Ti (TixOy) as a thin adhesive layer, and either a Si-wafer or Al foil as a substrate. Ppy films survive more than 6000 reduction-oxidation cycles in aqueous electrolyte without delamination. The possible mechanisms of enhanced adhesion are discussed. Those are: (1) increased adhesion due to changes in the chemical composition and surface structure of the pre-oxidized Ti, (2) the possibility of the chemical oxidation of pyrrole on the metal surface in addition to the electrochemical polymerization, (3) the adsorption of pyrrole molecules onto pre-oxidized Ti surface by interaction with Ti hydroxides on surface, and (4) the simultaneous growth of TixOy and Ppy.

  • 146.
    Idla, K
    et al.
    Tallinn Tech Univ, Dept Basic & Appl Chem, Chem Phys Lab, EE-19086 Tallinn, Estonia Helsinki Univ Technol, Ctr Chem Anal, FIN-02015 Espoo, Finland Linkoping Univ, Dept Phys, Appl Phys Lab, S-58183 Linkoping, Sweden.
    Johansson, LS
    Campbell, JM
    Tallinn Tech Univ, Dept Basic & Appl Chem, Chem Phys Lab, EE-19086 Tallinn, Estonia Helsinki Univ Technol, Ctr Chem Anal, FIN-02015 Espoo, Finland Linkoping Univ, Dept Phys, Appl Phys Lab, S-58183 Linkoping, Sweden.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    XPS and SIMS study: adhesion of polypyrrole film on titanium2000In: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 30, no 1, p. 557-560Article in journal (Refereed)
    Abstract [en]

    We have investigated why chemically preoxidized Ti (TixOy) shows strongly enhanced adhesion towards electrochemically deposited polypyrrole (Ppy) films as compared to Ti substrate with only native oxide overlayers, The XPS and SIMS results indicate that considerable amounts of TixOy are present 50-200 nm above the nominal Ppy interface. On the basis of XPS background analysis, supported by the results of SIMS, we suggest that the formation of a titanium-Ppy intermediate layer during the electrochemical synthesis leads to the enhanced adhesion observed. Copyright (C) 2000 John Wiley & Sons, Ltd.

  • 147.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Holmgren Peterson, Kajsa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Krogh, Magnus
    Micromuscle AB, Linköping.
    Skoglund, Mia
    Micromuscle AB, Linköping.
    Selbing, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Conjugated-polymer micro- and milliactuators for biological applications2002In: MRS bulletin, ISSN 0883-7694, E-ISSN 1938-1425, Vol. 27, no 6, p. 461-464Article in journal (Refereed)
    Abstract [en]

    The development of new conjugated-polymer tools for the study of the biological realm, and for use in a clinical setting, is reviewed in this article. Conjugated-polymer actuators, based on the changes of volume of the active conjugated polymer during redox transformation, can be used in electrolytes employed in cell-culture media and in biological fluids such as blood, plasma, and urine. Actuators ranging in size from 10 μm to 100 μm suitable for building structures to manipulate single cells are produced with photolithographic techniques. Larger actuators may be used for the manipulation of blood vessels and biological tissue.

  • 148.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Jager, Edwin W.H.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Peterson, K.H.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Altered impedance during pigment aggregation in Xenopus laevis melanophores2003In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 41, no 3, p. 357-364Article in journal (Refereed)
    Abstract [en]

    Melanophores are dark-brown pigment cells located in the skin of amphibia, fish and many invertebrates. The skin colour of these organisms is regulated by the translocation of pigment organelles, and the pigment distribution can be altered by external stimuli. The ability to change colour in response to stimuli makes these cells of interest for biosensing applications. It was investigated whether pigment aggregation in Xenopus laevis melanophores can be detected by impedance measurements performed in transparent microvials. The results show that cell attachment, cell spreading and pigment aggregation all resulted in impedance changes, seen particularly at the highest frequency tested (10 kHz). The mechanisms behind the impedance changes were investigated by the addition of latrunculin or melatonin, both of which cause pigment aggregation. The latrunculin-induced aggregation was associated with cell area decrease and filamentous actin (F-actin) breakdown, processes that can influence the impedance. Lack of F-actin breakdown and an increase in cell area during melatonin-induced aggregation suggest that some other intracellular process also contributes to the impedance decrease seen for melatonin. It was shown that impedance measurements reflect not only cell attachment and cell spreading, but also intracellular events.

  • 149.
    Infahsaeng, Yingyot
    et al.
    Thammasat University, Thailand; Lund University, Sweden.
    Danna, Daniele
    Lund University, Sweden.
    Tang, Zheng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Pascher, Torbjorn
    Lund University, Sweden.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sundstrom, Villy
    Lund University, Sweden.
    Yartsev, Arkady
    Lund University, Sweden.
    Transient photocurrent of bulk heterojunction solar cell characterized by ns-laser and sub-ms LED2015In: INTERNATIONAL CONFERENCE ON PHOTONICS SOLUTIONS 2015, SPIE-INT SOC OPTICAL ENGINEERING , 2015, Vol. 9659, no UNSP 96591CConference paper (Refereed)
    Abstract [en]

    We measure the transient photocurrent of APFO3:PCBM bulk heterojunction solar cells illuminated with ns-laser and sub-ms LED light sources. The ratio of the number of collective charges to the number of excited photon (external quantum efficiency, EQE) and the transient photocurrent fall times have been carried out with difference pulse durations and fluences. The EQEs characterized by ns-laser source are shown to obey the bimolecular recombination at high excitation fluences. The increasing of transient photocurrent fall times suggests that the fall times of free charge carriers are effected by deep trap density of state (DoS) and thus the free charge carriers have a sufficient time for bimolecular recombination at short circuit condition. At the same fluences, however, the EQEs characterized by sub-ms LED sources exhibit an excitation fluences independence of EQE. The transient photocurrent fall times with sub-ms LED sources are rather constant when the excitation fluences increases indicating that the deep trap DoS has less effect at short circuit condition for longer pulse duration.

  • 150.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Alternating Copolymers of Fluorence for Wide Spectral Coverage and Good Electrical Transport in Polymer Solar Cells2006In: MRS meeting, Boston Nov 26-Dec 1,2006, 2006Conference paper (Other academic)
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