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  • 1.
    Andersson, L Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Charge transport and energetic disorder in polymer: fullerene blends2011In: ORGANIC ELECTRONICS, ISSN 1566-1199, Vol. 12, no 2, p. 300-305Article in journal (Refereed)
    Abstract [en]

    Mobility versus temperature measurements on two different polymer: fullerene blends intended for solar cell applications have been evaluated in terms of the energetic disorder and how this varies with stoichiometry. The charge transport is shown to be confined to the intended phases in both cases, but with fundamentally different interaction properties. In one case the energetic disorder is a function of stoichiometry for the hole transport, while it is constant and equal to that of the pure fullerene for electrons, and in the other case it is the hole transport that has a stoichiometry independent energetic disorder. Transport site dilution is argued to be present in the fixed energetic disorder system and this is offered as a partial explanation to molecular weight dependent currents in solar cells. Determination of the glass transition temperature through the use of field effect transistors is also demonstrated.

  • 2.
    Andersson, Lars Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Electronic Transport in Polymeric Solar Cells and Transistors2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The main topic of this dissertation is electronic charge transport in polymeric and molecular organic materials and material blends intended for solar cell applications. Charge transport in polymers is a strange beast and carrier mobility is rarely a well-defined number. Measurements on different sample geometries and under different conditions tend to give different results and when everything is to be related to solar cell performance it is imperative that there is a way to correlate the results from different measurements. Polymer solar cells utilize composite materials for their function. This puts an additional twist on charge transport studies, as there will also be interaction between the different phases to take into account.

    Several measurement techniques have been used and their interrelationships as well as information on their relevance for solar cells have been investigated. Field effect transistors (FET) with an organic active layer have proved to be one of the more versatile measurement geometries and are also an interesting topic in itself. FETs are discussed both as a route for material characterization and as components. A main result correlates bias stress in organic field effect transistors with the electronic structure of the material.

    Power conversion efficiency in solar cells is discussed with respect to electrical properties. The interaction of different blend materials and the impact of stoichiometry on transport properties in the active layer have been investigated. Results indicate that charge transport properties frequently are a key determining factor for which material combinations and ratios that works best.

    Some work on the conductive properties of nano-fibers coated with semiconducting polymers has also been done and is briefly discussed. The conductive properties of nano-fibers have been studied through potential imaging.

    List of papers
    1. Non-equilibrium effects on electronic transport in organic field effect transistors
    Open this publication in new window or tab >>Non-equilibrium effects on electronic transport in organic field effect transistors
    2007 (English)In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 8, no 4, p. 423-430Article in journal (Refereed) Published
    Abstract [en]

    Non-ideal behavior in organic field effect transistors, in particular threshold voltage drift and light sensitivity, is argued to be due to intrinsic carrier dynamics. The discussion is based on the theory for hopping transport within a Gaussian density of states. Carrier concentration is shown to be of fundamental importance, and the time required to reach equilibrium at different bias is responsible for device behavior, with implications for mobility evaluation. Experimental results from various conjugated polymers in a field effect transistor illustrate the theory.

    Keywords
    Organic field-effect transistors (OFETs), Conjugated polymer, Hysteresis, Charge transport, Gaussian disorder model, Bias stress
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-12822 (URN)10.1016/j.orgel.2007.02.001 (DOI)
    Available from: 2007-12-05 Created: 2007-12-05 Last updated: 2017-12-14
    2. Bipolar transport observed through extraction currents on organic photovoltaic blend materials
    Open this publication in new window or tab >>Bipolar transport observed through extraction currents on organic photovoltaic blend materials
    2006 (English)In: Applied Physics Letters, ISSN 0003-6951, Vol. 89, p. 142111-Article in journal (Refereed) Published
    Abstract [en]

    Both electron and hole mobilities have been simultaneously measured through charge extraction by linearly increasing voltage on polymer heterojunction solar cells with varying stoichiometry of polymer and acceptor. The polymer is a low band gap copolymer of fluorene, thiophene, and electron accepting groups named APFO-Green 5, and the acceptor is [6,6]-phenyl-C61-butyric acid methylester. Results are correlated to field effect transistor measurements on the same material system. A monotonous increase in mobility for both carrier types is observed with increased acceptor loading.

    Keywords
    polymer blends, organic semiconductors, fullerene compounds, solar cells, electron mobility, hole mobility, stoichiometry, carrier density
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-12823 (URN)10.1063/1.2360199 (DOI)
    Available from: 2007-12-05 Created: 2007-12-05
    3. Stoichiometry, mobility, and performance in bulk heterojunction solar cells
    Open this publication in new window or tab >>Stoichiometry, mobility, and performance in bulk heterojunction solar cells
    2007 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, no 7, p. 071108-Article in journal (Refereed) Published
    Abstract [en]

    Bipolar transport in blends of a copolymer of fluorene, thiophene and electron accepting groups, and the substituted fullerene [6,6]-phenyl-C61-butyric acid methylester have been studied through charge extraction by linearly increasing voltage on solar cells and with field effect transistors. Between 10% and 90% polymer has been used and the results show a clear correlation to solar cell performance. Optimal solar cells comprise 20% polymer and have a power conversion efficiency of 3.5%. The electron mobility is increasing strongly with fullerene content, but is always lower than the hole mobility, thus explaining the low amount of polymer in optimized devices.

    Keywords
    electron mobility, field effect transistors, fullerenes, hole mobility, polymer blends, solar cells, stoichiometry
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-12824 (URN)10.1063/1.2771524 (DOI)
    Available from: 2007-12-05 Created: 2007-12-05 Last updated: 2017-12-14
    4. Acceptor influence on hole mobility in fullerene blends with alternating copolymers of fluorene
    Open this publication in new window or tab >>Acceptor influence on hole mobility in fullerene blends with alternating copolymers of fluorene
    2006 (English)In: Applied Physics Letters, ISSN 0003-6951, Vol. 88, p. 082103-Article in journal (Refereed) Published
    Abstract [en]

    Hole mobility in polyfluorene/fullerene blends has been studied with field effect transistors. Two different C60 derivatives and one C70 derivative have been investigated together with two different polyfluorenes. Mobility is presented as a function of acceptor loading at ratios suitable for photovoltaics and varies between 10–3 and 10–5  cm2  V–1  s–1 depending on the polymer/acceptor combination. The hole mobility is increased in blends with the commonly used acceptor [6-6]-phenyl-C61-butyric acid methylester (PCBM). With related C60 and C70 derivatives the hole mobility is decreased under the same circumstances.

    Keywords
    fullerenes, polymer blends, hole mobility, impurities, field effect transistors
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-12825 (URN)10.1063/1.2177663 (DOI)
    Available from: 2007-12-05 Created: 2007-12-05
    5. Intrinsic and extrinsic influences on the temperature dependence of mobility in conjugated polymers
    Open this publication in new window or tab >>Intrinsic and extrinsic influences on the temperature dependence of mobility in conjugated polymers
    Show others...
    2008 (English)In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 9, no 5, p. 569-574Article in journal (Refereed) Published
    Abstract [en]

    The temperature dependence of charge carrier mobility in conjugated polymers and their blends with fullerenes is investigated with different electrical methods, through field effect transistor (FET), space charge limited current (SCLC) and charge extraction (CELIV) measurements. Simple models, such as the Gaussian disorder model (GDM), are shown to accurately predict the temperature behavior, and a good correlation between the different measurement methods is obtained. Inconsistent charge carrier concentrations in the modeling are explained through intrinsic non-equilibrium effects, and are responsible for the limited applicability of existing numerical models. A severe extrinsic influence from water in FETs with a hydrophilic insulator interface is also demonstrated. The presence of water leads to a significant overestimate of the disorder in the materials from measurements close to room temperature and erratic behavior in the 150-350 K range. To circumvent this problem it is shown to be necessary to measure under ultra high vacuum (UHV) conditions. © 2008 Elsevier B.V. All rights reserved.

    Place, publisher, year, edition, pages
    Elsevier, 2008
    Keywords
    Electrical transport, Field effect transistor, Fullerene, Mobility, Polymer, Temperature dependence
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-50043 (URN)10.1016/j.orgel.2008.03.002 (DOI)
    Note

    The previous status of this article was Manuscript.

    Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12Bibliographically approved
  • 3.
    Andersson, Lars Mattias
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Topics in color measurement2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Color characterizations of printing situations are essential for a correct color reproduction. To obtain a good color characterization, knowledge about the substrate, the printing process and the printer function are all of great importance. In this thesis, methods for color characterization of printing situations are proposed and the problems associated with the transfer of color characterization methods from spectrophotometers to flatbed scanners are extensively studied. All methods have been developed with bearing on digital printing technologies, although they can be applied to any printing system. Special emphasis has been put on the influence of paper properties in printing situations and image capturing of printed substrates.

  • 4.
    Andersson, Lars Mattias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Acceptor influence on hole mobility in fullerene blends with alternating copolymers of fluorene2006In: Applied Physics Letters, ISSN 0003-6951, Vol. 88, p. 082103-Article in journal (Refereed)
    Abstract [en]

    Hole mobility in polyfluorene/fullerene blends has been studied with field effect transistors. Two different C60 derivatives and one C70 derivative have been investigated together with two different polyfluorenes. Mobility is presented as a function of acceptor loading at ratios suitable for photovoltaics and varies between 10–3 and 10–5  cm2  V–1  s–1 depending on the polymer/acceptor combination. The hole mobility is increased in blends with the commonly used acceptor [6-6]-phenyl-C61-butyric acid methylester (PCBM). With related C60 and C70 derivatives the hole mobility is decreased under the same circumstances.

  • 5.
    Andersson, Lars Mattias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Non-equilibrium effects on electronic transport in organic field effect transistors2007In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 8, no 4, p. 423-430Article in journal (Refereed)
    Abstract [en]

    Non-ideal behavior in organic field effect transistors, in particular threshold voltage drift and light sensitivity, is argued to be due to intrinsic carrier dynamics. The discussion is based on the theory for hopping transport within a Gaussian density of states. Carrier concentration is shown to be of fundamental importance, and the time required to reach equilibrium at different bias is responsible for device behavior, with implications for mobility evaluation. Experimental results from various conjugated polymers in a field effect transistor illustrate the theory.

  • 6.
    Andersson, Lars Mattias
    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.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Bipolar transport observed through extraction currents on organic photovoltaic blend materials2006In: Applied Physics Letters, ISSN 0003-6951, Vol. 89, p. 142111-Article in journal (Refereed)
    Abstract [en]

    Both electron and hole mobilities have been simultaneously measured through charge extraction by linearly increasing voltage on polymer heterojunction solar cells with varying stoichiometry of polymer and acceptor. The polymer is a low band gap copolymer of fluorene, thiophene, and electron accepting groups named APFO-Green 5, and the acceptor is [6,6]-phenyl-C61-butyric acid methylester. Results are correlated to field effect transistor measurements on the same material system. A monotonous increase in mobility for both carrier types is observed with increased acceptor loading.

  • 7.
    Andersson, Lars Mattias
    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.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Stoichiometry, mobility, and performance in bulk heterojunction solar cells2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, no 7, p. 071108-Article in journal (Refereed)
    Abstract [en]

    Bipolar transport in blends of a copolymer of fluorene, thiophene and electron accepting groups, and the substituted fullerene [6,6]-phenyl-C61-butyric acid methylester have been studied through charge extraction by linearly increasing voltage on solar cells and with field effect transistors. Between 10% and 90% polymer has been used and the results show a clear correlation to solar cell performance. Optimal solar cells comprise 20% polymer and have a power conversion efficiency of 3.5%. The electron mobility is increasing strongly with fullerene content, but is always lower than the hole mobility, thus explaining the low amount of polymer in optimized devices.

  • 8.
    Andersson, Mattias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Hedstrom, Svante
    Lund University, Sweden .
    Persson, Petter
    Lund University, Sweden .
    Conformation sensitive charge transport in conjugated polymers2013In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 103, no 21, p. 213303-Article in journal (Refereed)
    Abstract [en]

    Temperature dependent charge carrier mobility measurements using field effect transistors and density functional theory calculations are combined to show how the conformation dependent frontier orbital delocalization influences the hole-and electron mobilities in a donor-acceptor based polymer. A conformationally sensitive lowest unoccupied molecular orbital results in an electron mobility that decreases with increasing temperature above room temperature, while a conformationally stable highest occupied molecular orbital is consistent with a conventional hole mobility behavior and also proposed to be one of the reasons for why the material works well as a hole transporter in amorphous bulk heterojunction solar cells.

  • 9.
    Andersson, Mattias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Hsu, Yu-Te
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Health Sciences.
    Vandewal, Koen
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sieval, Alexander B
    Solenne BV, Groningen, The Netherlands.
    Andersson, Mats R.
    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.
    Mixed C60/C70 based fullerene acceptors in polymer bulk-heterojunction solar cells2012In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 13, no 12, p. 2856-2864Article in journal (Refereed)
    Abstract [en]

    Different mixtures of identically substituted C60 and C70 based fullerens have been used as acceptors in three polymer: fullerene systems that strongly express various performance limiting aspects of bulk heterojunction solar cells. Results are correlated with, and discussed in terms of e.g. morphology, charge separation, and charge transport. In these systems, there appears to be no relevant differences in either mobility or energy level positions between the identically substituted C60 and C70 based fullerenes tested. Examples of how fullerene mixtures influence the nano-morphology of the active layer are given. An upper limit to the open circuit voltage that can be obtained with fullerenes is also suggested.

  • 10.
    Andersson, Mattias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs , Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    From short to long - Optical and electrical transients in photovoltaic bulk heterojunctions of polyfluorene/fullerenes2009In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 357, no 1-3, p. 120-123Article in journal (Refereed)
    Abstract [en]

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

  • 11.
    Andersson, Mattias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Mueller, Christian
    Esfera UAB.
    Badada, Bekele H
    University of Cincinnati.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Wuerful, Uli
    Fraunhofer Institute Solar Energy Syst ISE.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Mobility and fill factor correlation in geminate recombination limited solar cells2011In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 110, no 2, p. 024509-Article in journal (Refereed)
    Abstract [en]

    Empirical data for the fill factor as a function of charge carrier mobility for two different polymer: fullerene systems is presented and analyzed. The results indicate that charge extraction depth limitations and space charge effects are inconsistent with the observed behavior, and the decrease in the fill factor is, instead, attributed to the field-dependent charge separation and geminate recombination. A solar cell photocurrent limited by the Onsager-Braun charge transfer exciton dissociation is shown to be able to accommodate the experimental observations. Charge dissociation limited solar cells always benefit from increased mobilities, and the negative contribution from the reduced charge separation is shown to be much more important for the fill factor in these material systems than any adverse effects from charge carrier extraction depth limitations or space charge effects due to unbalanced mobilities. The logarithmic dependence of the fill factor on the mobility for such a process is also shown to imply that simply increasing the mobilities is an impractical way to reach very high fill factors under these conditions since unrealistically high mobilities are required. A more controlled morphology is, instead, argued to be necessary for high performance.

  • 12.
    Andersson, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics.
    Osikowicz, Wojciech
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry.
    Jakobsson, Fredrik L.E.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Lindgren, L.
    Polymer Chemistry, Department of Materials and Surface Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Andersson, M.R.
    Polymer Chemistry, Department of Materials and Surface Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics.
    Intrinsic and extrinsic influences on the temperature dependence of mobility in conjugated polymers2008In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 9, no 5, p. 569-574Article in journal (Refereed)
    Abstract [en]

    The temperature dependence of charge carrier mobility in conjugated polymers and their blends with fullerenes is investigated with different electrical methods, through field effect transistor (FET), space charge limited current (SCLC) and charge extraction (CELIV) measurements. Simple models, such as the Gaussian disorder model (GDM), are shown to accurately predict the temperature behavior, and a good correlation between the different measurement methods is obtained. Inconsistent charge carrier concentrations in the modeling are explained through intrinsic non-equilibrium effects, and are responsible for the limited applicability of existing numerical models. A severe extrinsic influence from water in FETs with a hydrophilic insulator interface is also demonstrated. The presence of water leads to a significant overestimate of the disorder in the materials from measurements close to room temperature and erratic behavior in the 150-350 K range. To circumvent this problem it is shown to be necessary to measure under ultra high vacuum (UHV) conditions. © 2008 Elsevier B.V. All rights reserved.

  • 13.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Sun, Zhengyi
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Energy Level Bending in Ultrathin Polymer Layers Obtained through Langmuir-Shafer Deposition2016In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 7, p. 1077-1084Article in journal (Refereed)
    Abstract [en]

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

  • 14.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Sun, Zhengyi
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    The energetics of the semiconducting polymer-electrode interface for solution-processed electronicsManuscript (preprint) (Other academic)
    Abstract [en]

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

  • 15.
    Chen, Miaoxiang
    et al.
    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.
    Perzon, Erik
    Department of Materials and Surface Chemistry, Polymer Technology, Chalmers University of Technology, Göteborg, Sweden .
    Andersson, Mats R
    Department of Materials and Surface Chemistry, Polymer Technology, Chalmers University of Technology, Göteborg, Sweden .
    Pullerits, Tönu
    Department of Chemical Physics, Lund University, Lund, Sweden .
    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.
    Berggren, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    High carrier mobility in low band gap polymer-based field-effect transistors2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 87, no 25, p. 252105-1-252105-3Article in journal (Refereed)
    Abstract [en]

    A conjugated polymer with a low band gap of 1.21 eV, i.e., absorbing infrared light, is demonstrated as active material in field-effect transistors (FETs). The material consists of alternating fluorene units and low band gap segments with electron donor-acceptor-donor units composed of two electron-donating thiophene rings attached on both sides of a thiadiazolo-quinoxaline electron-acceptor group. The polymer is solution-processable and air-stable; the resulting FETs exhibit typical p-channel characteristics and field-effect mobility of 0.03 cm2 V−1 s−1.

  • 16.
    Gadisa, Abay
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Mammo, W.
    Addis Ababa University.
    Andersson, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Admassie, S.
    Addis Ababa University.
    Zhang, Fengling
    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.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    A New Donor-Acceptor-Donor Polyfluorence Copolymer with Balanced Electron and Hole Mobility2007In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 0000, no 00Article in journal (Refereed)
  • 17.
    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.

  • 18.
    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.

  • 19.
    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.

  • 20.
    J Lindgren, Lars
    et al.
    Chalmers.
    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.
    Barrau, Sophie
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hellstrom, Stefan
    Chalmers.
    Mammo, Wendimagegn
    Chalmers.
    Perzon, Erik
    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.
    Synthesis, Characterization, and Devices of a Series of Alternating Copolymers for Solar Cells2009In: CHEMISTRY OF MATERIALS, ISSN 0897-4756, Vol. 21, no 15, p. 3491-3502Article in journal (Refereed)
    Abstract [en]

    In this study we report the synthesis, characterization. and photovoltaic properties of a series of six Conjugated polymers based on donor-acceptor-donor (DAD) structure. The polymers are obtained via Suzuki polymerization of different alkoxy-substituted DAD monomers together with a substituted fluorene or phenylene monomer. Application of polymers as light-harvesting and electron-donating materials in solar cells, in conjunction with both [60]PCBM and [70]PCBM as acceptors, show power-conversion efficiencies (PCEs) up to 2.9%, values obtained without extensive optimization work. Furthermore, atomic force microscopy and field-effect transistor (FET) mobility measurements of acceptor-polymer mixtures show that differences in substitution on the polymers affect morphology, mobility, and device performance. Within the series of polymers, all showing similar optical absorption and redox behavior, substituents play an important role in phase separation on a micrometer scale, which in turn has a large impact on device performance. The phase-separation behavior is clearly seen in [70]PCBM devices where the best-performing devices are obtained using the polymers with short alkoxy groups or no substituents together with a high speed of spin coating during device preparation.

  • 21.
    Krebs, Frederik C
    et al.
    Tech University Denmark, Riso Natl Lab Sustainable Energy, DK-4000 Roskilde, Denmark .
    Gevorgyan, Suren A
    Tech University Denmark, Riso Natl Lab Sustainable Energy, DK-4000 Roskilde, Denmark .
    Gholamkhass, Bobak
    Simon Fraser University, Burnaby, BC V5A 1S6 Canada .
    Holdcroft, Steven
    Simon Fraser University, Burnaby, BC V5A 1S6 Canada .
    Schlenker, Cody
    University So Calif, Department Chemistry, Loker Hydrocarbon Research Institute, Los Angeles, CA 90089 USA Centre Energy Nanosci and Technology, Los Angeles, CA 90089 USA .
    Thompson, Mark E
    University So Calif, Department Chemistry, Loker Hydrocarbon Research Institute, Los Angeles, CA 90089 USA Centre Energy Nanosci and Technology, Los Angeles, CA 90089 USA .
    Thompson, Barry C
    University So Calif, Department Chemistry, Loker Hydrocarbon Research Institute, Los Angeles, CA 90089 USA Centre Energy Nanosci and Technology, Los Angeles, CA 90089 USA .
    Olson, Dana
    NREL, Golden, CO 80401 USA .
    Ginley, David S
    NREL, Golden, CO 80401 USA .
    Shaheen, Sean E
    NREL, Golden, CO 80401 USA University Denver, Department Phys and Astron, Denver, CO 80208 USA .
    Alshareef, Husam N
    University Texas Dallas, Richardson, TX 75080 USA .
    Murphy, John W
    University Texas Dallas, Richardson, TX 75080 USA .
    Youngblood, W Justin
    University N Texas, Department Chemistry, Denton, TX 76201 USA .
    Heston, Nathan C
    University Florida, Department Phys, Centre Macromol Science and Engn, Gainesville, FL 32611 USA .
    Reynolds, John R
    University Florida, Department Chemistry, Centre Macromol Science and Engn, Gainesville, FL 32611 USA .
    Jia, Shijun
    Plextronics Inc, Pittsburgh, PA 15238 USA .
    Laird, Darin
    Plextronics Inc, Pittsburgh, PA 15238 USA .
    Tuladhar, Sachetan M
    University London Imperial Coll Science Technology and Med, Department Phys, Blackett Lab, London SW7 2AZ, England .
    Dane, Justin G A
    University London Imperial Coll Science Technology and Med, Department Phys, Blackett Lab, London SW7 2AZ, England .
    Atienzar, Pedro
    University London Imperial Coll Science Technology and Med, Department Phys, Blackett Lab, London SW7 2AZ, England .
    Nelson, Jenny
    University London Imperial Coll Science Technology and Med, Department Phys, Blackett Lab, London SW7 2AZ, England .
    Kroon, Jan M
    ECN Solar Energy, NL-1755 ZG Petten, Netherlands .
    Wienk, Martijn M
    Eindhoven University Technology, Lab Macromol and Organ Chemistry, NL-5600 MB Eindhoven, Netherlands .
    Janssen, Rene A J
    Eindhoven University Technology, Lab Macromol and Organ Chemistry, NL-5600 MB Eindhoven, Netherlands .
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Lira-Cantu, Monica
    Centre Invest Nanociencia and Nanotecnol, E-08193 Barcelona, Spain .
    de Bettignies, Remi
    CEA INES DRI, Lab Composants Solaires, F-73377 Le Bourget Du lac, France .
    Guillerez, Stephane
    CEA INES DRI, Lab Composants Solaires, F-73377 Le Bourget Du lac, France .
    Aernouts, Tom
    IMEC, PV Department, B-3001 Louvain, Belgium .
    Cheyns, David
    IMEC, PV Department, B-3001 Louvain, Belgium .
    Lutsen, Laurence
    IMEC, IMOMEC, B-3590 Diepenbeek, Belgium .
    Zimmermann, Birger
    Fraunhofer Institute Solare Energiesyst ISE, Department Mat Research and Appl Opt, D-79110 Freiburg, Germany .
    Wuerfel, Uli
    Fraunhofer Institute Solare Energiesyst ISE, Department Mat Research and Appl Opt, D-79110 Freiburg, Germany .
    Niggemann, Michael
    Fraunhofer Institute Solare Energiesyst ISE, Department Mat Research and Appl Opt, D-79110 Freiburg, Germany .
    Schleiermacher, Hans-Frieder
    Fraunhofer Institute Solare Energiesyst ISE, Department Mat Research and Appl Opt, D-79110 Freiburg, Germany .
    Liska, Paul
    Ecole Polytech Fed Lausanne, LPI, Institute Chemistry Science and Engn, Fac Basic Science, CH-1015 Lausanne, Switzerland .
    Graetzel, Michael
    Ecole Polytech Fed Lausanne, LPI, Institute Chemistry Science and Engn, Fac Basic Science, CH-1015 Lausanne, Switzerland .
    Lianos, Panagiotis
    University Patras, Department Engn Science, Patras 26500, Greece .
    Katz, Eugene A
    Ben Gurion University Negev, Jacob Blaustein Institute Desert Research, Department Solar Energy and Environm Phys, IL-84990 Sede Boqer, Israel .
    Lohwasser, Wolfgang
    Alcan Packaging Singen GmbH, D-78221 Singen, Germany .
    Jannon, Bertrand
    Alcan Packaging Singen GmbH, D-78221 Singen, Germany .
    A round robin study of flexible large-area roll-to-roll processed polymer solar cell modules2009In: SOLAR ENERGY MATERIALS AND SOLAR CELLS, ISSN 0927-0248, Vol. 93, no 11, p. 1968-1977Article in journal (Refereed)
    Abstract [en]

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

  • 22.
    Li, Weiwei
    et al.
    Chinese Academy of Science.
    Qin, Ruiping
    Beijing Normal University.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology. 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.
    Li, Fenghong
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Zhang, Chi
    Chinese Academy of Science.
    Li, Binsong
    Chinese Academy of Science.
    Liu, Zhengping
    Beijing Normal University.
    Bo, Zhishan
    Chinese Academy of Science.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Tailoring side chains of low band gap polymers for high efficiency polymer solar cells2010In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 51, no 14, p. 3031-3038Article in journal (Refereed)
    Abstract [en]

    High efficiency organic solar cells (OSCs) require conjugated polymers with a low band gap, broad absorption in visible and IR region, high carrier mobility, and relatively high molecular weight as p-type donor materials. Flexible side chains on the rigid polymer backbone are crucial for the solubility of conjugated polymers. In this work, four polymers with the main chain structure of fluorene-thiophene-benzothiadiazole-thiophene and flexible side chains located on fluorene, thiophene, and benzothiadiazole moiety, respectively, have been synthesized by Suzuki-Miyaura-Schluter polycondensation. Photovoltaic device measurements with a device configuration of ITO/polymer:PC71BM blends/LiF/Al show that P1 carrying octyloxy chains on benzothiadiazole rings gives the best performance, with a power conversion efficiency of 3.1%.

  • 23.
    Li, Weiwei
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhou, Yi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Viktor
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Thomann, Yi
    Freiburg Material Research Centre, Germany.
    Veit, Clemens
    Fraunhofer Institute for Solar Energy Systems, Germany.
    Tvingstedt, Kristofer
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Qin, Ruiping
    Beijing Normal University, China.
    Bo, Zhishan
    Beijing Normal University, China.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wuerfel, Uli
    Freiburg Material Research Centre, Germany.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    The Effect of additive on performance and shelf-stability of HSX-1/PCBM photovoltaic devices2011In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 12, no 9, p. 1544-1551Article in journal (Refereed)
    Abstract [en]

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

  • 24.
    Müller, Christian
    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.
    Pena-Rodriguez, Ovidio
    Esfera UAB, Spain .
    Garriga, Miquel
    Esfera UAB, Spain .
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Campoy-Quiles, Mariano
    Esfera UAB, Spain .
    Determination of Thermal Transition Depth Profiles in Polymer Semiconductor Films with Ellipsometry2013In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 46, no 18, p. 7325-7331Article in journal (Refereed)
    Abstract [en]

    Geometric confinement and interface effects can significantly alter the thermodynamic properties of thin polymer films. Phase transition temperatures have been shown to strongly depend on film thickness below a critical thickness threshold. It has been suggested that this behavior is due to an interface-induced continuous variation in phase transition 200 temperatures throughout the depth of the films. Here we employ variable-temperature spectroscopic ellipsometry to demonstrate the existence of these depth profiles. We examine four different polymer semiconductors that are of interest for organic light-emitting diodes, solar cells, and field-effect transistors. In contrast to insulating polymers, these light-absorbing materials provide detailed information about structural changes as a function of depth due to wavelength-dependent attenuation. This concept enables us to investigate a broad range of thermodynamic processes including the glass transition, crystallization as well as crystalline and liquid-crystalline melting. In general, for the here investigated systems, higher transition temperatures are found at the free surface. Finally, the deduced profiles are used to predict the thickness dependence of the mean phase transition temperature.

  • 25.
    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.

  • 26.
    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.

  • 27.
    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)
  • 28.
    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).

  • 29.
    Tang, Zheng
    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.
    George, Zandra
    Chalmers University of Technology.
    Vandewal, Koen
    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.
    Heriksson, Patrik
    Chalmers University of Technology.
    Kroon, Renee
    Chalmers University of Technology.
    Andersson, Mats
    Chalmers University of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Interlayer for Modified Cathode in Highly Efficient Inverted ITO-Free Organic Solar Cells2012In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 24, no 4, p. 554-558Article in journal (Refereed)
    Abstract [en]

    Inverted polymer solar cells with a bottom metal cathode modified by a conjugated polymer interlayer show considerable improvement of photocurrent and fill factor, which is due to hole blocking at the interlayer, and a modified surface energy which affects the nanostructure in the TQ1/[70]PCBM blend.

  • 30.
    Tang, Zheng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    George, Zandra
    Chalmers, Sweden .
    Ma, Zaifei
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Bergqvist, Jonas
    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.
    Vandewal, Koen
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Ergang
    Chalmers, Sweden .
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Andersson, Mats R
    Chalmers, Sweden .
    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.
    Semi-Transparent Tandem Organic Solar Cells with 90% Internal Quantum Efficiency2012In: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 2, no 12, p. 1467-1476Article in journal (Refereed)
    Abstract [en]

    Semi-transparent (ST) organic solar cells with potential application as power generating windows are studied. The main challenge is to find proper transparent electrodes with desired electrical and optical properties. In this work, this is addressed by employing an amphiphilic conjugated polymer PFPA-1 modified ITO coated glass substrate as the ohmic electron-collecting cathode and PEDOT:PSS PH1000 as the hole-collecting anode. For active layers based on different donor polymers, considerably lower reflection and parasitic absorption are found in the ST solar cells as compared to solar cells in the standard geometry with an ITO/PEDOT:PSS anode and a LiF/Al cathode. The ST solar cells have remarkably high internal quantum efficiency at short circuit condition (similar to 90%) and high transmittance (similar to 50%). Hence, efficient ST tandem solar cells with enhanced power conversion efficiency (PCE) compared to a single ST solar cell can be constructed by connecting the stacked two ST sub-cells in parallel. The total loss of photons by reflection, parasitic absorption and transmission in the ST tandem solar cell can be smaller than the loss in a standard solar cell based on the same active materials. We demonstrate this by stacking five separately prepared ST cells on top of each other, to obtain a higher photocurrent than in an optimized standard solar cell.

  • 31.
    Yang, Yi
    et al.
    Chinese Academy of Science.
    Zhang, Jing
    Chinese Academy of Science.
    Zhou, Ye
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Zhao, Guangjin
    Chinese Academy of Science.
    He, Chang
    Chinese Academy of Science.
    Li, Yongfang
    Chinese Academy of Science.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Solution-Processable Organic Molecule with Triphenylamine Core and Two Benzothiadiazole-Thiophene Arms for Photovoltaic Application2010In: JOURNAL OF PHYSICAL CHEMISTRY C, ISSN 1932-7447, Vol. 114, no 8, p. 3701-3706Article in journal (Refereed)
    Abstract [en]

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

  • 32.
    Zhang, Fengling
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Mammo, Wendimagegn
    Addis Ababa Univeristy.
    Andersson, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Admassie, Shimelis
    Addis Ababa Univeristy.
    Andersson, Mats R
    Chalmers University of Technology.
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Low-Bandgap Alternating Fluorene Copolymer/Methanofullerene Heterojunctions in Efficient Near-Infrared Polymer Solar Cells2006In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 18, p. 2169-2173Article in journal (Refereed)
1 - 32 of 32
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