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  • 501.
    Stehr, Jan Eric
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Chen, Shula
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Cai, Li
    Xi'an Jiaotong University, Shaanxi, China.
    Shen, Shaohua
    Xi'an Jiaotong University, Shaanxi, China.
    Buyanova, Irina A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Identification of a N-related acceptor in ZnO nanowires2019Konferensbidrag (Refereegranskat)
  • 502.
    Stehr, Jan Eric
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Pearton, Stephen
    Uecker, Reinhard
    Hofmann, Detlev
    Buyanova, Irina A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Electron paramagnetic resonance signatures of defects and impurities in β-Ga2O32019Konferensbidrag (Refereegranskat)
  • 503.
    Stehr, Jan Eric
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Shen, Shaohua
    Buyanova, Irina A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Effects of N implantation on defect formation in ZnO nanowires2018Konferensbidrag (Refereegranskat)
  • 504.
    Stehr, Jan Eric
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Hofmann, Detlev
    Justus-Liebig-University Giessen, Giessen, Germany.
    Schörmann, Jörg
    Justus-Liebig-University Giessen, Giessen, Germany.
    Becker, Martin
    Justus-Liebig-University Giessen, Giessen, Germany.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Buyanova, Irina A
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Electron paramagnetic resonance signatures of Co2+ and Cu2+ in β-Ga2O32019Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 115, nr 24, artikel-id 242101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gallium oxide (β-Ga2O3) is a wide-bandgap compound semiconductor with a bandgap of ∼4.9 eV that is currently considered promising for a wide range of applications ranging from transparent conducting electrodes to UV optoelectronic devices and power electronics. However, all of these applications require a reliable and precise control of electrical and optical properties of the material, which can be largely affected by impurities, such as transition metals commonly present during the growth. In this work, we employ electron paramagnetic resonance (EPR) spectroscopy to obtain EPR signatures of the 3d-transition metals Co2+ and Cu2+ in β-Ga2O3 bulk crystals and powders that were unknown so far. Furthermore, we show that both Co2+ and Cu2+ preferentially reside on the octahedral gallium lattice site.

  • 505.
    Stehr, Jan Eric
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensor- och aktuatorsystem. Linköpings universitet, Tekniska fakulteten.
    Karlsson, Jan Olof G.
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för läkemedelsforskning. Linköpings universitet, Medicinska fakulteten.
    Evidence that fodipir (DPDP) binds neurotoxic Pt2+ with a high affinity: An electron paramagnetic resonance study2019Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, artikel-id 15813Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Oxaliplatin typically causes acute neuropathic problems, which may, in a dose-dependent manner, develop into a chronic form of chemotherapy-induced peripheral neuropathy (CIPN), which is associated with retention of Pt2+ in the dorsal root ganglion. A clinical study by Coriat and co-workers suggests that co-treatment with mangafodipir [Manganese(II) DiPyridoxyl DiPhosphate; MnDPDP] cures ongoing CIPN. These authors anticipated that it is the manganese superoxide dismutase mimetic activity of MnDPDP that explains its curative activity. However, this is questionable from a pharmacokinetic perspective. Another, but until recently undisclosed possibility is that Pt2+ outcompetes Mn2+/Ca2+/Zn2+ for binding to DPDP or its dephosphorylated metabolite PLED (diPyridoxyL EthylDiamine) and transforms toxic Pt2+ into a non-toxic complex, which can be readily excreted from the body. We have used electron paramagnetic resonance guided competition experiments between MnDPDP (10logKML ≈ 15) and K2PtCl4, and between MnDPDP and ZnCl2 (10logKML ≈ 19), respectively, in order to obtain an estimate the 10logKML of PtDPDP. Optical absorption spectroscopy revealed a unique absorption line at 255 nm for PtDPDP. The experimental data suggest that PtDPDP has a higher formation constant than that of ZnDPDP, i.e., higher than 19. The present results suggest that DPDP/PLED has a high enough affinity for Pt2+ acting as an efficacious drug in chronic Pt2+-associated CIPN.

  • 506.
    Sun, Huiliang
    et al.
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Liu, Tao
    HKUST, Peoples R China.
    Yu, Jianwei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Lau, Tsz-Ki
    Chinese Univ Hong Kong, Peoples R China.
    Zhang, Guangye
    eFlexPV Ltd, Peoples R China.
    Zhang, Yujie
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Su, Mengyao
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Tang, Yumin
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Ma, Ruijie
    HKUST, Peoples R China; HKUST, Peoples R China.
    Liu, Bin
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Liang, Jiaen
    HKUST, Peoples R China; HKUST, Peoples R China.
    Feng, Kui
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Lu, Xinhui
    Chinese Univ Hong Kong, Peoples R China.
    Guo, Xugang
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yan, He
    HKUST, Peoples R China; HKUST, Peoples R China.
    A monothiophene unit incorporating both fluoro and ester substitution enabling high-performance donor polymers for non-fullerene solar cells with 16.4% efficiency2019Ingår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 12, nr 11, s. 3328-3337Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thiophene and its derivatives have been extensively used in organic electronics, particularly in the field of polymer solar cells (PSCs). Significant research efforts have been dedicated to modifying thiophene-based units by attaching electron-donating or withdrawing groups to tune the energy levels of conjugated materials. Herein, we report the design and synthesis of a novel thiophene derivative, FE-T, featuring a monothiophene functionalized with both an electron-withdrawing fluorine atom (F) and an ester group (E). The FE-T unit possesses distinctive advantages of both F and E groups, the synergistic effects of which enable significant downshifting of the energy levels and enhanced aggregation/crystallinity of the resulting organic materials. Shown in this work are a series of polymers obtained by incorporating the FE-T unit into a PM6 polymer to fine-tune the energetics and morphology of this high-performance PSC material. The optimal polymer in the series shows a downshifted HOMO and an improved morphology, leading to a high PCE of 16.4% with a small energy loss (0.53 eV) enabled by the reduced non-radiative energy loss (0.23 eV), which are among the best values reported for non-fullerene PSCs to date. This work shows that the FE-T unit is a promising building block to construct donor polymers for high-performance organic photovoltaic cells.

  • 507.
    Sun, Qing
    et al.
    Heidelberg University, Germany.
    Fassl, Paul
    Heidelberg University, Germany.
    Becker-Koch, David
    Heidelberg University, Germany.
    Bausch, Alexandra
    Heidelberg University, Germany.
    Rivkin, Boris
    Heidelberg University, Germany.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. University of Oxford, England.
    Hopkinson, Paul E.
    Heidelberg University, Germany.
    Snaith, Henry J.
    University of Oxford, England.
    Vaynzof, Yana
    Heidelberg University, Germany.
    Role of Microstructure in Oxygen Induced Photodegradation of Methylammonium Lead Triiodide Perovskite Films2017Ingår i: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 7, nr 20, artikel-id 1700977Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper investigates the impact of microstructure on the degradation rate of methylammonium lead triiodide (MAPbI(3)) perovskite films upon exposure to light and oxygen. By comparing the oxygen induced degradation of perovskite films of different microstructure-fabricated using either a lead acetate trihydrate precursor or a solvent engineering technique-it is demonstrated that films with larger and more uniform grains and better electronic quality show a significantly reduced degradation compared to films with smaller, more irregular grains. The effect of degradation on the optical, compositional, and microstructural properties of the perovskite layers is characterized and it is demonstrated that oxygen induced degradation is initiated at the layer surface and grain boundaries. It is found that under illumination, irreversible degradation can occur at oxygen levels as low as 1%, suggesting that degradation can commence already during the device fabrication stage. Finally, this work establishes that improved thin-film microstructure, with large uniform grains and a low density of defects, is a prerequisite for enhanced stability necessary in order to make MAPbI(3) a promising long lived and low cost alternative for future photovoltaic applications.

  • 508.
    Sun, Wenjun
    et al.
    Chalmers, Sweden .
    Ma, Zaifei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Dang, Dongfeng
    Chalmers, Sweden .
    Zhu, Weiguo
    Xiangtan University, Peoples R China .
    Andersson, Mats R.
    Chalmers, Sweden .
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Wang, Ergang
    Chalmers, Sweden .
    An alternating D-A(1)-D-A(2) copolymer containing two electron-deficient moieties for efficient polymer solar cells2013Ingår i: JOURNAL OF MATERIALS CHEMISTRY A, ISSN 2050-7488, Vol. 1, nr 37, s. 11141-11144Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Unlike normal donor-acceptor (D-A) polymers containing only one electron-deficient segment in their repeating unit, the incorporation of two electron-deficient moieties with different absorption behaviors, forming a D-A(1)-D-A(2) internal structure in the alternating copolymer, showed a broader absorption spectrum than its constituent parts and enhanced photovoltaic performance. This work is anticipated to open the door to the design of new low bandgap polymers with a broader absorption range for efficient polymer solar cells.

  • 509.
    Svensson, M.
    et al.
    Dept. of Organ. Chem. and Polymer T., Chalmers University of Technology, SE-41296 Gothenburg, Sweden.
    Theander, M.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Andersson, M.R.
    Dept. of Organ. Chem. and Polymer T., Chalmers University of Technology, SE-41296 Gothenburg, Sweden.
    Synthesis and properties of new polythiophenes with high photoluminescence efficiency2001Ingår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 119, nr 1-3, s. 113-114Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis of three regioregular alkoxy-substituted phenyl polythiophenes is described. The polythiophenes exhibited photoluminescence efficiency. The yields were synthesized using FeCl3 polymerization.

  • 510.
    Svensson, M.
    et al.
    Department of Organic Chemistry and Polymer Technology, Chalmers University of Technology, S-41296 Göteborg, Sweden.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Andersson, M.R.
    Department of Organic Chemistry and Polymer Technology, Chalmers University of Technology, S-41296 Göteborg, Sweden.
    Synthesis and properties of alternating polyfluorene copolymers with redshifted absorption for use in solar cells2003Ingår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 135-136, s. 137-138Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three fluorene based alternating copolymers with redshifted absorption were synthesized and used as the active layer in photodiodes. The polymers are soluble in common solvents. The photodiodes cover a large part of the solar spectrum with high external quantum efficiency and we reach 2.4% power conversion efficiency for the best device in this study. 

  • 511.
    Svensson, M.
    et al.
    Dept. of Organ. Chemistry Technology, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
    Zhang, Fengling
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Veenstra, S.C.
    Ener. Res. Ctr. Netherlands (ECN), Solar Energy, P.O. Box 1, NL-1755 ZG Petten, Netherlands.
    Verhees, W.J.H.
    Ener. Res. Ctr. Netherlands (ECN), Solar Energy, P.O. Box 1, NL-1755 ZG Petten, Netherlands.
    Hummelen, J.C.
    Stratingh Institute, University of Groningen, Nijenborgh 4, NL-9747 AG Groningen, Netherlands.
    Kroon, J.M.
    Ener. Res. Ctr. Netherlands (ECN), Solar Energy, P.O. Box 1, NL-1755 ZG Petten, Netherlands.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Andersson, M.R.
    Dept. of Organ. Chemistry Technology, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
    High-performance polymer solar cells of an alternating polyfluorene copolymer and a fullerene derivative2003Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 15, nr 12, s. 988-991Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High-performance polymer solar cells of an alternating polyfluorene copolymer, PFDTBT, and a fullerene derivative were studied. It was shown that PFDTBT is a promising candidate for obtaining high energy conversion efficiency when combined with a suitable electron acceptor. Results showed that high-performance solar cells with extended spectral coverage and increased open-circuit voltage could be prepared from composites prepared from electron acceptor.

  • 512.
    Tan, Yeshu
    et al.
    Soochow Univ, Peoples R China.
    Zou, Yatao
    Soochow Univ, Peoples R China.
    Wu, Linzhong
    Soochow Univ, Peoples R China.
    Huang, Qi
    Soochow Univ, Peoples R China.
    Yang, Di
    Soochow Univ, Peoples R China.
    Chen, Min
    Soochow Univ, Peoples R China.
    Ban, Muyang
    Soochow Univ, Peoples R China.
    Wu, Chen
    Soochow Univ, Peoples R China.
    Wu, Tian
    Soochow Univ, Peoples R China.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Song, Tao
    Soochow Univ, Peoples R China.
    Zhang, Qiao
    Soochow Univ, Peoples R China.
    Sun, Baoquan
    Soochow Univ, Peoples R China.
    Highly Luminescent and Stable Perovskite Nanocrystals with Octylphosphonic Acid as a Ligand for Efficient Light-Emitting Diodes2018Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 4, s. 3784-3792Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    All inorganic perovskite nanocrystals (NCs) of CsPbX3 (X = Cl, Br, I, or their mixture) are regarded as promising candidates for high-performance light-emitting diode (LED) owing to their high photoluminescence (PL) quantum yield (QY) and easy synthetic process. However, CsPbX3 NCs synthesized by the existing methods, where oleic acid (OA) and oleylamine (OLA) are generally used as surface-chelating ligands, suffer from poor stability due to the ligand loss, which drastically deteriorates their PL QY, as well as dispersibility in solvents. Herein, the OA/OLA ligands are replaced with octylphosphonic acid (OPA), which dramatically enhances the CsPbX3 stability. Owing to a strong interaction between OPA and lead atoms, the OPA-capped CsPbX3 (OPA-CsPbX3) NCs not only preserve their high PL QY (amp;gt;90%) but also achieve a high-quality dispersion in solvents after multiple purification processes. Moreover, the organic residue in purified OPA-CsPbBr3 is only similar to 4.6%, which is much lower than similar to 29.7% in OA/OLA-CsPbBr3. Thereby, a uniform and compact OPA-CsPbBr3 film is obtained for LED application. A green LED with a current efficiency of 18.13 cd A(-1), corresponding to an external quantum efficiency of 6.5%, is obtained. Our research provides a path to prepare high-quality perovskite NCs for high-performance optoelectronic devices.

  • 513.
    Tanaka, H.
    et al.
    Kyushu University.
    Herland, Anna
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Lindgren, L.J.
    Chalmers univeristy of Technology.
    Tsutsui, T.
    Kyushu University.
    Andersson, Mats R
    Chalmers univeristy of Technology.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Enhanced current efficiency from Bio-Organic light-emitting diodes using decorated amyloid fibrils with conjugated polymer2008Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, nr 9, s. 2858-2861Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrate the use of self-assembled bionanostructures in polymer light-emitting diodes. Amyloid fibrils formed by protein misfolding were decorated with a soluble luminescent conjugated polymer. This conjugated polymer complex with amyloid fibrils was used as the active layer in a light emitting diode, resulting in a 10-fold increase in external quantum efficiency compared with pristine polymer, because of improved carrier injection. © 2008 American Chemical Society.

  • 514.
    Tang, Ailing
    et al.
    Natl Ctr Nanosci and Technol, Peoples R China.
    Xiao, Bo
    Natl Ctr Nanosci and Technol, Peoples R China.
    Wang, Yuming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Tajima, Keisuke
    RIKEN Ctr Emergent Matter Sci CEMS, Japan.
    Bin, Haijun
    Chinese Acad Sci, Peoples R China.
    Zhang, Zhi-Guo
    Chinese Acad Sci, Peoples R China.
    Li, Yongfang
    Chinese Acad Sci, Peoples R China.
    Wei, Zhixiang
    Natl Ctr Nanosci and Technol, Peoples R China.
    Zhou, Erjun
    Natl Ctr Nanosci and Technol, Peoples R China.
    Simultaneously Achieved High Open-Circuit Voltage and Efficient Charge Generation by Fine-Tuning Charge-Transfer Driving Force in Nonfullerene Polymer Solar Cells2018Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, nr 6, artikel-id 1704507Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To maximize the short-circuit current density (J(SC)) and the open circuit voltage (V-OC) simultaneously is a highly important but challenging issue in organic solar cells (OSCs). In this study, a benzotriazole-based p-type polymer (J61) and three benzotriazole-based nonfullerene small molecule acceptors (BTA1-3) are chosen to investigate the energetic driving force for the efficient charge transfer. The lowest unoccupied molecular orbital (LUMO) energy levels of small molecule acceptors can be fine-tuned by modifying the end-capping units, leading to high V-OC (1.15-1.30 V) of OSCs. Particularly, the LUMO energy level of BTA3 satisfies the criteria for efficient charge generation, which results in a high V-OC of 1.15 V, nearly 65% external quantum efficiency, and a high power conversion efficiency (PCE) of 8.25%. This is one of the highest V-OC in the high-performance OSCs reported to date. The results imply that it is promising to achieve both high J(SC) and V-OC to realize high PCE with the carefully designed nonfullerene acceptors.

  • 515.
    Tang, Qun
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Solin, Niclas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Hybrid bioinorganic insulin amyloid fibrils2010Ingår i: CHEMICAL COMMUNICATIONS, ISSN 1359-7345, Vol. 46, nr 23, s. 4157-4159Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 516.
    Tang, Zheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Chargeand Light Management in Organic Solar Cells2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Solar cells based on organic materials are extensively investigated both in academia and industry, owing to their potential of being inexpensive, lightweight, flexible and suitable for roll-to-roll production. Performance of organic solar cells has been rapidly improving, and the state of the art organic solar cells have an efficiency over 10%.

    This thesis aims to provide a comprehensive study of device engineering and device physics of organic solar cells. The ambition has been to investigate and optimize the conditions for light in-coupling and charge extraction in organic solar cells with alternative geometries. The ultimate goal is to propose methods that could potentially get the power conversion efficiency of organic solar cells with industrially compatible geometries over the current limit of 10%.

    To achieve such a goal, we employed a conjugated polymer as an interface modifier to improve the surface and electrical properties of substrate electrodes for solar cells with active layers based on blends containing conjugated polymers and fullerenes. A possibility of improving photovoltaic performance of easily fabricated reverse geometry solar cells (bottom metal cathode/active layer/top  transparent anode) has been demonstrated via this simple interface modification. Systematic investigations revealed that the enhanced device performance was not only related to the modified active layer/electrode interface but also changes in the bulk of the active layer. Consequently, the device performance of a reversed solar cell was found to be as good as that of a standard solar cell. The understanding of the effects of the interlayer modification on the performance of reversed solar cells, and the methodology provided in this thesis is a guideline for further studying and developing interface materials for highly efficient organic solar cells.

    An ITO electrode was further converted into a cathode by the polymer interlayer to construct semi-transparent solar cells with great potentials for building integrated photovoltaic applications. By stacking semi-transparent solar cells on top of each other, we showed that light can be more efficiently harvested compared to a conventional architecture solar cell. It has also been demonstrated that semitransparent solar cells combined with macroscopic light trapping elements can also be highly efficient.

    However, this thesis is not only about papers that I have published as a graduate student. The first five chapters have been included to provide background in the field of organic photovoltaics.

    Delarbeten
    1. Interlayer for Modified Cathode in Highly Efficient Inverted ITO-Free Organic Solar Cells
    Öppna denna publikation i ny flik eller fönster >>Interlayer for Modified Cathode in Highly Efficient Inverted ITO-Free Organic Solar Cells
    Visa övriga...
    2012 (Engelska)Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 24, nr 4, s. 554-558Artikel i tidskrift (Refereegranskat) Published
    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.

    Ort, förlag, år, upplaga, sidor
    Wiley-Blackwell, 2012
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-74183 (URN)10.1002/adma.201104579 (DOI)
    Tillgänglig från: 2012-01-20 Skapad: 2012-01-20 Senast uppdaterad: 2017-12-08
    2. Universal modification of poor cathodes into good ones by a polymer interlayer for high performance reversed organic solar cells
    Öppna denna publikation i ny flik eller fönster >>Universal modification of poor cathodes into good ones by a polymer interlayer for high performance reversed organic solar cells
    Visa övriga...
    2014 (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    In organic bulk-heterojunction solar cells, energy losses at the active layer/electrode interface are often observed. Modification of these interfaces with organic interlayers optimizes charge carrier injection and extraction and thus improves device performance. In this work, the effects of cathode modification by a conjugated polymer interlayer PFPA1 on the performance of reversed organic solar cells (substrate/cathode/active layer/transparent anode) based on different active material systems and different substrate electrodes are systematically investigated. A reduction of the work function irrespective of the substrate cathode used is observed upon the deposition of the PFPA1 interlayer; further related to an improved built-in electric field and open-circuit voltage. The amphiphilic character of the PFPA1 interlayer alters the surface energy of the substrate cathode, leading to the formation of a better active layer morphology aiding efficient exciton dissociation and photocurrent extraction in the modified solar cells. Hence, internal quantum efficiency is found significantly higher than that of their unmodified counterparts, while optically, the modified and unmodified solar cells are identical. Moreover, the deep HOMO of the PFPA1 interlayer improves the selectivity for all investigated substrate cathodes, thus enhancing the fill factor. We demonstrate a possibility of improving photovoltaic performance of reversed solar cells via a simple and universal interface modification and provide the basic guidelines for development and characterization of interface materials for organic solar cells in general.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-103928 (URN)
    Tillgänglig från: 2014-02-03 Skapad: 2014-02-03 Senast uppdaterad: 2018-09-01Bibliografiskt granskad
    3. Semi-Transparent Tandem Organic Solar Cells with 90% Internal Quantum Efficiency
    Öppna denna publikation i ny flik eller fönster >>Semi-Transparent Tandem Organic Solar Cells with 90% Internal Quantum Efficiency
    Visa övriga...
    2012 (Engelska)Ingår i: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 2, nr 12, s. 1467-1476Artikel i tidskrift (Refereegranskat) Published
    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.

    Ort, förlag, år, upplaga, sidor
    Wiley-VCH Verlag Berlin, 2012
    Nyckelord
    polymer solar cells, semi-transparent solar cells, interface, conjugated polymers, tandem solar cells
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-86894 (URN)10.1002/aenm.201200204 (DOI)000312035800008 ()
    Anmärkning

    Funding Agencies|Swedish Energy Agency||Swedish Research Council||Advanced Functional Materials initiative at Linkoping University||Knut and Alice Wallenberg Foundation (KAW)||KAW||VINNOVA||

    Tillgänglig från: 2013-01-07 Skapad: 2013-01-07 Senast uppdaterad: 2015-05-29
    4. Light trapping with total internal reflection and transparent electrodes in organic photovoltaic devices
    Öppna denna publikation i ny flik eller fönster >>Light trapping with total internal reflection and transparent electrodes in organic photovoltaic devices
    2012 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, nr 16Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Herein, we demonstrate a method to build highly efficient light trapping structures for printed organic solar cells and modules, compatible with roll to roll manufacturing. Echelle grating structures in combination with semitransparent electrodes allow for efficient light trapping via means of total internal reflection. With this method, we demonstrate an increased cell photocurrent response up to 24%, compared to a standard cell configuration with a planar reflector. The demonstrated light trapping approach is expected to be even more useful for photovoltaic modules, where light hitting "dead areas" in between the sub-cells comprising the module will now be utilized.

    Ort, förlag, år, upplaga, sidor
    American Institute of Physics (AIP), 2012
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-87228 (URN)10.1063/1.4759125 (DOI)000310669300075 ()
    Tillgänglig från: 2013-01-14 Skapad: 2013-01-14 Senast uppdaterad: 2017-12-06
    5. Light Trapping with Dielectric Scatterers in Single- and Tandem-Junction Organic Solar Cells
    Öppna denna publikation i ny flik eller fönster >>Light Trapping with Dielectric Scatterers in Single- and Tandem-Junction Organic Solar Cells
    Visa övriga...
    2013 (Engelska)Ingår i: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 3, nr 12, s. 1606-1613Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Efficient dielectric scatterers based on a mixture of TiO2 nanoparticles and polydimethylsiloxane are demonstratedfor light trapping in semitransparent organic solar cells. An improvement of 80% in the photocurrent of an optimized semitransparent solar cell is achieved with the dielectric scatterer with approximate to 100% diffuse reflectance for wavelengths larger than 400 nm. For a parallel tandem solar cell, the dielectric scatterer generates 20% more photocurrent compared with a silver mirror beneath the cell; for a series tandem solar cell, the dielectric scatterer can be used as a photocurrent balancer between the subcells with different photoabsorbing materials. The power conversion efficiency of the tandem cell in series configuration with balanced photocurrent in the subcells exceeds that of an optimized standard solar cell with a reflective electrode. The characteristics of polydimethylsiloxane, such as flexibility and the ability to stick conformably to surfaces, also remain in the dielectric scatterers, which makes the demonstrated light trapping configuration highly suitable for large scale module manufacturing of roll-to-roll printed organic single- or tandem-junction solar cells.

    Ort, förlag, år, upplaga, sidor
    Wiley-VCH Verlag, 2013
    Nyckelord
    light trapping; light scattering; organic solar cells; semitransparent solar cells; tandem solar cells
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-103295 (URN)10.1002/aenm.201300524 (DOI)000328337500012 ()
    Tillgänglig från: 2014-01-17 Skapad: 2014-01-16 Senast uppdaterad: 2014-02-03
    6. Light trapping in thin film organic solar cells
    Öppna denna publikation i ny flik eller fönster >>Light trapping in thin film organic solar cells
    2014 (Engelska)Ingår i: Materials Today, ISSN 1369-7021, E-ISSN 1873-4103, Vol. 17, nr 8, s. 389-396Artikel, forskningsöversikt (Refereegranskat) Published
    Abstract [en]

    A major issue in organic solar cells is the poor mobility and recombination of the photogenerated charge carriers. The active layer has to be kept thin to facilitate charge transport and minimize recombination losses. However, optical losses due to inefficient light absorption in the thin active layers can be considerable in organic solar cells. Therefore, light trapping schemes are critically important for efficient organic solar cells. Traditional light trapping schemes for thick solar cells need to be modified for organic thin film solar cells in which coherent optics and wave effects play a significant role. In this review, we discuss the light trapping schemes for organic thin film solar cells, which includes geometric engineering of the structure of the solar cell at the micro and nanoscale, plasmonic structures, and more.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2014
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-103929 (URN)10.1016/j.mattod.2014.05.008 (DOI)000344209800018 ()
    Tillgänglig från: 2014-02-03 Skapad: 2014-02-03 Senast uppdaterad: 2017-12-06Bibliografiskt granskad
  • 517.
    Tang, Zheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mattias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    George, Zandra
    Chalmers University of Technology.
    Vandewal, Koen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Tvingstedt, Kristofer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Heriksson, Patrik
    Chalmers University of Technology.
    Kroon, Renee
    Chalmers University of Technology.
    Andersson, Mats
    Chalmers University of Technology.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Interlayer for Modified Cathode in Highly Efficient Inverted ITO-Free Organic Solar Cells2012Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 24, nr 4, s. 554-558Artikel i tidskrift (Refereegranskat)
    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.

  • 518.
    Tang, Zheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Elfwing, Anders
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Bergqvist, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Tress, Wolfgang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Light Trapping with Dielectric Scatterers in Single- and Tandem-Junction Organic Solar Cells2013Ingår i: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 3, nr 12, s. 1606-1613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Efficient dielectric scatterers based on a mixture of TiO2 nanoparticles and polydimethylsiloxane are demonstratedfor light trapping in semitransparent organic solar cells. An improvement of 80% in the photocurrent of an optimized semitransparent solar cell is achieved with the dielectric scatterer with approximate to 100% diffuse reflectance for wavelengths larger than 400 nm. For a parallel tandem solar cell, the dielectric scatterer generates 20% more photocurrent compared with a silver mirror beneath the cell; for a series tandem solar cell, the dielectric scatterer can be used as a photocurrent balancer between the subcells with different photoabsorbing materials. The power conversion efficiency of the tandem cell in series configuration with balanced photocurrent in the subcells exceeds that of an optimized standard solar cell with a reflective electrode. The characteristics of polydimethylsiloxane, such as flexibility and the ability to stick conformably to surfaces, also remain in the dielectric scatterers, which makes the demonstrated light trapping configuration highly suitable for large scale module manufacturing of roll-to-roll printed organic single- or tandem-junction solar cells.

  • 519.
    Tang, Zheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Elfwing, Anders
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Melianas, Armantas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Bergqvist, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Bao, Qinye
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Fully-solution-processed organic solar cells with a highly efficient paper-based light trapping element2015Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, nr 48, s. 24289-24296Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrate the use of low cost paper as an efficient light-trapping element for thin film photovoltaics. We verify its use in fully-solution processed organic photovoltaic devices with the highest power conversion efficiency and the lowest internal electrical losses reported so far, the architecture of which - unlike most of the studied geometries to date - is suitable for upscaling, i.e. commercialization. The use of the paper-reflector enhances the external quantum efficiency (EQE) of the organic photovoltaic device by a factor of approximate to 1.5-2.5 over the solar spectrum, which rivals the light harvesting efficiency of a highly-reflective but also considerably more expensive silver mirror back-reflector. Moreover, by detailed theoretical and experimental analysis, we show that further improvements in the photovoltaic performance of organic solar cells employing PEDOT:PSS as both electrodes rely on the future development of high-conductivity and high-transmittance PEDOT:PSS. This is due optical losses in the PEDOT:PSS electrodes.

  • 520.
    Tang, Zheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    George, Zandra
    Chalmers, Sweden .
    Ma, Zaifei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Bergqvist, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Tvingstedt, Kristofer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Vandewal, Koen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Ergang
    Chalmers, Sweden .
    Andersson, Mattias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mats R
    Chalmers, Sweden .
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Semi-Transparent Tandem Organic Solar Cells with 90% Internal Quantum Efficiency2012Ingår i: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 2, nr 12, s. 1467-1476Artikel i tidskrift (Refereegranskat)
    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.

  • 521.
    Tang, Zheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Liu, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Melianas, Armantas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Bergqvist, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Tress, Wolfgang
    Ecole Polytech Federal Lausanne, Switzerland.
    Bao, Qinye
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Qian, Deping
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    A New Fullerene-Free Bulk-Heterojunction System for Efficient High-Voltage and High-Fill Factor Solution-Processed Organic Photovoltaics2015Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 27, nr 11, s. 1900-+Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Small molecule donor/polymer acceptor bulk-heterojunction films with both compounds strongly absorbing have great potential for further enhancement of the performance of organic solar cells. By employing a newly synthesized small molecule donor with a commercially available polymer acceptor in a solution-processed fullerene-free system, a high power conversion efficiency of close to 4% is reported.

  • 522.
    Tang, Zheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Tress, Wolfgang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Bao, Qinye
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Jafari, Mohammad Javad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska högskolan.
    Bergqvist, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mats R.
    , Chalmers University of Technology, Göteborg, Sweden; University of South Australia, Australia.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Improving Cathodes with a Polymer Interlayer in Reversed Organic Solar Cells2014Ingår i: Advanced Energy Materials, ISSN 1614-6832, Vol. 4, nr 15, artikel-id 1400643Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of cathode modification by a conjugated polymer interlayer PFPA1 on the performance of reversed organic solar cells (substrate/cathode/active layer/transparent anode) based on different active material systems and different substrate electrodes are systematically investigated. A reduction of the work function irrespective of the substrate cathode used is observed upon the deposition of the PFPA1 interlayer, which is further related to an improved built-in electric field and open-circuit voltage. The amphiphilic character of the PFPA1 interlayer alters the surface energy of the substrate cathode, leading to the formation of a better active layer morphology aiding efficient exciton dissociation and photocurrent extraction in the modified solar cells. Hence, internal quantum efficiency is found to be significantly higher than that of their unmodified counterparts, while optically, the modified and unmodified solar cells are identical. Moreover, the deep highest occupied molecular orbital (HOMO) of the PFPA1 interlayer improves the selectivity for all investigated substrate cathodes, thus enhancing the fill factor.

  • 523.
    Tang, Zheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Tress, Wolfgang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Bao, Qinye
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Jafari, Mohammad Javad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Bergqvist, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Andersson, Mats R.
    Polymer Technology, Department of Chemical and Biological Engineering, Chalmers University of Technology, Göteborg, Sweden.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Universal modification of poor cathodes into good ones by a polymer interlayer for high performance reversed organic solar cells2014Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    In organic bulk-heterojunction solar cells, energy losses at the active layer/electrode interface are often observed. Modification of these interfaces with organic interlayers optimizes charge carrier injection and extraction and thus improves device performance. In this work, the effects of cathode modification by a conjugated polymer interlayer PFPA1 on the performance of reversed organic solar cells (substrate/cathode/active layer/transparent anode) based on different active material systems and different substrate electrodes are systematically investigated. A reduction of the work function irrespective of the substrate cathode used is observed upon the deposition of the PFPA1 interlayer; further related to an improved built-in electric field and open-circuit voltage. The amphiphilic character of the PFPA1 interlayer alters the surface energy of the substrate cathode, leading to the formation of a better active layer morphology aiding efficient exciton dissociation and photocurrent extraction in the modified solar cells. Hence, internal quantum efficiency is found significantly higher than that of their unmodified counterparts, while optically, the modified and unmodified solar cells are identical. Moreover, the deep HOMO of the PFPA1 interlayer improves the selectivity for all investigated substrate cathodes, thus enhancing the fill factor. We demonstrate a possibility of improving photovoltaic performance of reversed solar cells via a simple and universal interface modification and provide the basic guidelines for development and characterization of interface materials for organic solar cells in general.

  • 524.
    Tang, Zheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Tress, Wolfgang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Light trapping in thin film organic solar cells2014Ingår i: Materials Today, ISSN 1369-7021, E-ISSN 1873-4103, Vol. 17, nr 8, s. 389-396Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    A major issue in organic solar cells is the poor mobility and recombination of the photogenerated charge carriers. The active layer has to be kept thin to facilitate charge transport and minimize recombination losses. However, optical losses due to inefficient light absorption in the thin active layers can be considerable in organic solar cells. Therefore, light trapping schemes are critically important for efficient organic solar cells. Traditional light trapping schemes for thick solar cells need to be modified for organic thin film solar cells in which coherent optics and wave effects play a significant role. In this review, we discuss the light trapping schemes for organic thin film solar cells, which includes geometric engineering of the structure of the solar cell at the micro and nanoscale, plasmonic structures, and more.

  • 525.
    Tang, Zheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten. Donghua Univ, Peoples R China.
    Wang, Jing
    Donghua Univ, Peoples R China.
    Melianas, Armantas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wu, Yang
    Xi An Jiao Tong Univ, Peoples R China.
    Kroon, Renee
    Chalmers Univ Technol, Sweden.
    Li, Weiwei
    Chinese Acad Sci, Peoples R China.
    Ma, Wei
    Xi An Jiao Tong Univ, Peoples R China.
    Andersson, Mats R.
    Flinders Univ S Australia, Australia.
    Ma, Zaifei
    Donghua Univ, Peoples R China.
    Wanzhu, Cai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Tress, Wolfgang
    Ecole Polytech Fed Lausanne, Switzerland.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Relating open-circuit voltage losses to the active layer morphology and contact selectivity in organic solar cells2018Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, nr 26, s. 12574-12581Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrate that voltage losses due to both radiative and non-radiative recombination of charge carriers are strongly dependent on D/A phase separation. By processing the active layer with various solvent additives, we create distinct morphologies that lead to significantly different device open-circuit voltages (V-OC), even though the charge transfer state energy (E-CT) of the D/A blend remains rather constant. We find that radiative recombination losses are significantly increased for a finely intermixed morphology, due to the large D/A interface area. This leads to a total recombination loss of E-CT - qV(OC) approximate to 0.7 eV. However, considerably smaller losses (0.5 eV), due to suppressed non-radiative recombination, are possible in solar cells where the D/A materials are organized to only allow for selective charge carrier extraction. Using a drift diffusion model, we show that the origin of the reduced non-radiative recombination losses is related to an effect which has not been considered for optimized solar cells - the suppression of minority carrier diffusion to the wrong contact. Our results suggest that the built-in field is not sufficiently strong even in optimized organic solar cells and that selective carrier extraction is critical for further improvements in V-OC.

  • 526.
    Tao, Qiang
    et al.
    Xiangtan University, Peoples R China; Chalmers, Sweden.
    Xia, Yuxin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Xu, Xiaofeng
    Chalmers, Sweden.
    Hedstrom, Svante
    Lund University, Sweden.
    Backe, Olof
    Chalmers, Sweden.
    James, David I.
    Chalmers, Sweden.
    Persson, Petter
    Lund University, Sweden.
    Olsson, Eva
    Chalmers, Sweden.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Hou, Lintao
    Jinan University, Peoples R China.
    Zhu, Weiguo
    Xiangtan University, Peoples R China.
    Wang, Ergang
    Chalmers, Sweden.
    D-A(1)-D-A(2) Copolymers with Extended Donor Segments for Efficient Polymer Solar Cells2015Ingår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 48, nr 4, s. 1009-1016Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Typically a donor-acceptor (D-A) design strategy is used for engineering the bandgap of polymers for solar cells. However, in this work, a series of alternating D-A(1-)D-A(2) copolymers PnTQTI(F) were synthesized and characterized with oligothiophenes (nT, n = 1, 2, 3) as the donor and two electron-deficient moieties, quinoxaline and isoindigo, as the acceptors in the repeating unit. We have studied the influence of the donor segments with different numbers of thiophene units and the effect of the addition of fluorine to the quinoxaline unit of the D-A(1)-D-A(2) polymers. The photophysical, electrochemical, and photovoltaic properties of the polymers were examined via a range of techniques and related to theoretical simulations. On increasing the length of the donor thiophene units, broader absorption spectra were observed in addition to a sequential increase in HOMO levels, while the LUMO levels displayed very small variations. The addition of fluorine to the quinoxaline unit not only decreased the HOMO levels of the resulting polymers but also enhanced the absorption coefficients. A superior photovoltaic performance was observed for the P3TQTI-F-based device with a power conversion efficiency (PCE) of 7.0%, which is the highest efficiency for alternating D-A(1)-D-A(2) polymers reported to date. The structureproperty correlations of the PnTQTI(F) polymers demonstrate that varying of the length of the donor segments is a valuable method for designing high-performance D-A(1)-D-A(2) copolymers and highlight the promising nature of D-A(1)-D-A(2) copolymers for efficient bulk-heterojunction solar cells.

  • 527.
    Tauber, Daniela
    et al.
    Lund Univ, Sweden.
    Cai, Weidong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Scheblykin, Ivan G.
    Lund Univ, Sweden.
    Macroscopic Domains within an Oriented TQ1 Film Visualized Using 2D Polarization Imaging2017Ingår i: ACS OMEGA, ISSN 2470-1343, Vol. 2, nr 1, s. 32-40Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Large-area self-assembly of functional conjugated polymers holds a great potential for practical applications of organic electronic devices. We obtained well-aligned films of poly[2,3-bis(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1) using the floating film transfer method. Thereby, a droplet of the TQ1 solution was injected on top of the surface of an immiscible liquid substrate, at the meniscus formed at the edge of a Petri dish, from where the polymer solution and the film spread in one direction. Characterization of the TQ1 film using the recently developed two-dimensional polarization imaging (2D POLIM) revealed large, millimeter-sized domains of oriented polymer chains. The irregular shape of the contact line at the droplet source induced the appearance of disordered stripes perpendicular to the spreading direction. A correlation of polarization parameters measured using 2D POLIM revealed the microstructure of such stripes, providing valuable information for further improvement and possible upscaling of this promising method.

  • 528.
    Tauber, Daniela
    et al.
    Lund University, Sweden.
    Tian, Yuxi
    Lund University, Sweden.
    Xia, Yuxin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Scheblykin, Ivan G.
    Lund University, Sweden.
    Nanoscale Chain Alignment and Morphology in All-Polymer Blends Visualized Using 2D Polarization Fluorescence Imaging: Correlation to Power Conversion Efficiencies in Solar Cells2017Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, nr 40, s. 21848-21856Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    All-polymer blends are promising materials for organic electronics. Their performance critically depends on the quality of mixing of the electron donor and acceptor polymers and on the local chain organization. We investigated spatially resolved photoluminescence properties of as-prepared and annealed blends of poly[2,3-bis(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1) and poly(N,N-bis-2-octyldodecyl-naphtalene-1,4,5,8-bisdicarboximide-2,6-diyl-alt- 5,5-2,2-bithiophene) (N2200) using two-dimensional polarization imaging (2D POLIM). N2200 is known to aggregate into fiber-like morphologies with a few hundreds of nanometers lateral extensions. Our findings suggest a highly parallel chain organization within individual domains. Comparing blends differing in the batch of the N2200 component, we could relate decreased power conversion efficiencies of the corresponding devices to aggregation of N2200 in tens of micrometer-sized elongated structures. TQ1 showed less sensitivity to preparation conditions. Other than N2200, TQ1 is liquid crystalline, and its side chain structure hinders aggregation. It thus might be feasible to consider similar properties for the design of acceptor polymers as well.

  • 529.
    Teixeira, A.I.
    et al.
    Karolinska Institute.
    Ilkhanizadeh, S.
    Karolinska Institute.
    Wigenius, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Duckworth, J.K.
    Karolinska Institute.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Hermanson, O.
    Karolinska Institute.
    The promotion of neuronal maturation on soft substrates2009Ingår i: Biomaterials, ISSN 0142-9612, Vol. 30, nr 27, s. 4567-4572Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Microenvironmental mechanical properties of stem cell niches vary across tissues and developmental stages. Accumulating evidence suggests that matching substrate elasticity with in vivo tissue elasticity facilitates stem cell differentiation. However, it has not been established whether substrate elasticity can control the maturation stage of cells generated by stem cell differentiation. Here we show that soft substrates with elasticities commensurable to the elasticity of the brain promote the maturation of neural stem cell-derived neurons. In the absence of added growth factors, neurons differentiated on soft substrates displayed long neurites and presynaptic terminals, contrasting with the bipolar immature morphology of neurons differentiated on stiff substrates. Further, soft substrates supported an increase in astrocytic differentiation. However, stiffness cues could not override the dependency of astrocytic differentiation on Notch signaling. These results demonstrate that substrate elasticity per se can drive neuronal maturation thus defining a crucial parameter in neuronal differentiation of stem cells.

  • 530.
    Thaning, Elin M
    et al.
    Royal Institute of Technology.
    Asplund, Maria L M
    Royal Institute of Technology.
    Nyberg, Tobias A
    Royal Institute of Technology.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    von Hoist, Hans
    Royal Institute of Technology.
    Stability of Poly(3,4-ethylene dioxythiophene) Materials Intended for Implants2010Ingår i: JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS, ISSN 1552-4973, Vol. 93B, nr 2, s. 407-415Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 531.
    Theander, M
    et al.
    Linkoping Univ, Dept Phys, IFM, Appl Phys Lab, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden Univ Lund, Dept Chem Phys, S-22100 Lund, Sweden.
    Granlund, T
    Linkoping Univ, Dept Phys, IFM, Appl Phys Lab, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden Univ Lund, Dept Chem Phys, S-22100 Lund, Sweden.
    Johanson, DM
    Linkoping Univ, Dept Phys, IFM, Appl Phys Lab, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden Univ Lund, Dept Chem Phys, S-22100 Lund, Sweden.
    Ruseckas, A
    Linkoping Univ, Dept Phys, IFM, Appl Phys Lab, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden Univ Lund, Dept Chem Phys, S-22100 Lund, Sweden.
    Sundstrom, V
    Linkoping Univ, Dept Phys, IFM, Appl Phys Lab, S-58183 Linkoping, Sweden Chalmers Univ Technol, Dept Organ Chem & Polymer Technol, S-41296 Gothenburg, Sweden Univ Lund, Dept Chem Phys, S-22100 Lund, Sweden.
    Andersson, MR
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Lasing in a microcavity with an oriented liquid-crystalline polyfluorene copolymer as active layer2001Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 13, nr 5, s. 323-327Artikel i tidskrift (Refereegranskat)
  • 532. Theander, M.
    et al.
    Johansson, D.M.
    Dept. of Organ. Chem. and Polymer T., Chalmers University of Technology, S-412 96 Göteborg, Sweden.
    Ruseckas, A.
    Department of Chemical Physics, Chemical Center, Lund University, S-221 00 Lund, Sweden.
    Zigmantas, D.
    Department of Chemical Physics, Chemical Center, Lund University, S-221 00 Lund, Sweden.
    Andersson, M.R.
    Dept. of Organ. Chem. and Polymer T., Chalmers University of Technology, S-412 96 Göteborg, Sweden.
    Sundstrom, V.
    Sundström, V., Department of Chemical Physics, Chemical Center, Lund University, S-221 00 Lund, Sweden.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Interchain photoluminescence in substituted polyfluorenes2001Ingår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 119, nr 1-3, s. 615-616Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have characterised the interchain emitting states of two substituted polyfluorenes with steady-state and time-resolved photoluminescence (PL). Site selective excitation of the interchain state shows that physical dimers are formed in the film. These dimers have low concentration in the films but exciton diffusion to the dimers is reducing the intrachain exciton lifetime. With asymmetrical substituents, the PL quantum yield is higher and the PL lifetime is longer due to lower concentration of dimers. Slow cooling from the melt, gives a new red shifted emission band and less intrachain emission. A discrepancy in the calculated radiative lifetimes suggest a fast formation of this new band.

  • 533. Theander, M.
    et al.
    Svensson, M.
    Department of Polymer Technology, Chalmers Univ. of Technol., S-412 96, Göteborg, Sweden.
    Ruseckas, A.
    Department of Chemical Physics, Lund University, S-221 00, Lund, Sweden.
    Zigmantas, D.
    Department of Chemical Physics, Lund University, S-221 00, Lund, Sweden.
    Sundstrom, V.
    Sundström, V., Department of Chemical Physics, Lund University, S-221 00, Lund, Sweden.
    Andersson, M.R.
    Department of Polymer Technology, Chalmers Univ. of Technol., S-412 96, Göteborg, Sweden.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    High luminescence from a substituted polythiophene in a solvent with low solubility2001Ingår i: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 337, nr 4-6, s. 277-283Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Steady-state and time-resolved photoluminescence (PL) is used to probe different states of order in highly regular poly(3-(2'-methoxy-5'-octylphenyl)thiophene) (POMeOPT). In a good solvent (chloroform) the polymer has a PL yield of 0.33 and in a solvent with low solubility (mixture of chloroform and toluene) a new phase appears with higher PL yield (0.50). The new phase is attributed to micro-crystals formed by the regular part of the polymer which have low solubility in toluene. The crystallites have highly structured and redshifted electronic transitions compared with chains which are dissolved.

  • 534.
    Thinprakong, Chorpure
    Linköpings universitet. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Excitation transfer between conjugated polyelectrolytes and triplet emitter confined in protein nanowires2010Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Phosphorescent metal complexes can be incorporated into amyloid-like fibrils, and these fibrils can be decorated with conjugated polyelectrolytes (CPEs). In this study, fac-tris[2-phenylpyridinato-C2,N]irdium(III) complexes [Ir(piq)3] were used as the phosphorescence emitter and Sodium-poly(3-thiophene acetic acid) (PTAA-Na) compounds were used as CPEs. Herein we study the energy transfer processes between the iridium complexes and the CPEs. To investigate these mechanisms, the analysis of the emission quenching and time-resolved measurements were done. Our measurements show that energy can be transfered from singlet state of PTAA to the singlet state of Ir(piq)3. Moreover, incorporation of iridium into amyloid fibrils decreases the importance of energy transfer by the Dexter mechanism. Finally we propose a geometry of interaction to explain the obtained results.

  • 535.
    Tian, Rong
    et al.
    Tsinghua Peking Joint Ctr Life Sci, Peoples R China.
    Ning, Weihua
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Nanjing Tech Univ, Peoples R China.
    Chen, Minghai
    Chinese Acad Sci, Peoples R China.
    Zhang, Cheng
    Peking Univ, Peoples R China.
    Li, Qingwen
    Chinese Acad Sci, Peoples R China.
    Bai, Jingwei
    Tsinghua Univ, Peoples R China.
    High performance electrochemical biosensor based on 3D nitrogen-doped reduced graphene oxide electrode and tetrahedral DNA nanostructure2019Ingår i: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 194, s. 273-281Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, an electrochemical biosensor was developed for highly sensitive and specific detection of target miRNA-155. The structure was formed by the hybridization of a tetrahedral DNA nanostructure-based biomolecular probe assembled on 3D nitrogen-doped reduced graphene oxide/gold nanoparticles (3D N-doped rGO/AuNPs) electrode surface. Upon addition of target miRNA-155, the gold and silver nanorod/thionine/complementary DNA (AuAgNR/Thi/F) was hybridized with the target, and used for signal amplification, catalyzing the reduction of Thi as an electron mediator. Due to the signal amplification by the enhanced immobilization of DNA on the surface of 3D N-doped rGO/AuNPs electrode and AuAgNR/Thi, coupling the low background signal produced by blank solution, electrochemical performance of the device was optimized to be proportional to miRNA-155 concentration in the range of 1 x 10(-11) to 1 x 10(-4) M with a detection limit of 1 x 10(-12) M. In addition, direct detection in serum is demonstrated with high specificity. Thus, this biosensor is potentially applicable for microRNA detection in medical research and early clinical diagnosis.

    Publikationen är tillgänglig i fulltext från 2020-10-09 12:20
  • 536.
    Tiwari, Ashutosh
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Responsive nanomaterials for emerging bioelectronics2012Konferensbidrag (Refereegranskat)
  • 537.
    Tress, Wolfgang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Organic Solar Cells: Theory, Experiment, and Device Simulation2014Bok (Refereegranskat)
    Abstract [en]

    This book covers in a textbook-like fashion the basics or organic solar cells, addressing the limits of photovoltaic energy conversion and giving a well-illustrated introduction to molecular electronics with focus on the working principle and characterization of organic solar cells. Further chapters based on the author’s dissertation focus on the electrical processes in organic solar cells by presenting a detailed drift-diffusion approach to describe exciton separation and charge-carrier transport and extraction. The results, although elaborated on small-molecule solar cells and with focus on the zinc phthalocyanine: C60 material system, are of general nature. They propose and demonstrate experimental approaches for getting a deeper understanding of the dominating processes in amorphous thin-film based solar cells in general.

     The main focus is on the interpretation of the current-voltage characteristics (J-V curve). This very standard measurement technique for a solar cell reflects the electrical processes in the device. Comparing experimental to simulation data, the author discusses the reasons for S-Shaped J-V curves, the role of charge carrier mobilities and energy barriers at interfaces, the dominating recombination mechanisms, the charge carrier generation profile, and other efficiency-limiting processes in organic solar cells. The book concludes with an illustrative guideline on how to identify reasons for changes in the J-V curve.

     This book is a suitable introduction for students in engineering, physics, material science, and chemistry starting in the field of organic or hybrid thin-film photovoltaics. It is just as valuable for professionals and experimentalists who analyze solar cell devices.

  • 538.
    Tress, Wolfgang
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Swiss Federal Institute Technology EPFL, Switzerland.
    Beyer, Beatrice
    Fraunhofer Institute Electron Beam Plasma Technology and CO, Germany.
    Ashari Astani, Negar
    Ecole Polytech Federal Lausanne, Switzerland.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Meloni, Simone
    Ecole Polytech Federal Lausanne, Switzerland.
    Rothlisberger, Ursula
    Ecole Polytech Federal Lausanne, Switzerland.
    Extended Intermolecular Interactions Governing Photocurrent-Voltage Relations in Ternary Organic Solar Cells2016Ingår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 7, nr 19, s. 3936-3944Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Efficient organic solar cells are based on (electron) donor-acceptor heterojunctions. An optically generated excited molecular state (exciton) is dissociated at this junction, forming a charge-transfer (CT) state in an intermediate step before the electron and hole are completely separated. The observed highly efficient dissociation of this Coulombically bound state raises the question on the dissociation mechanism. Here, we show that the observed high quantum yields of charge carrier generation and CT state dissociation are due to extended (and consequently weakly bound) CT states visible in absorption and emission spectra and first-principles calculations. Identifying a new geminate-pair loss mechanism via donor excimers, we find that the hole on the small-molecule donor is not localized on a single molecule and charge separation is correlated with the energetic offset between excimer and CT states. Thus, the charges upon interface charge transfer and even in the case of back-transfer and recombination are less localized than commonly assumed.

  • 539.
    Tress, Wolfgang
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Simple experimental test to distinguish extraction and injection barriers at the electrodes of (organic) solar cells with S-shaped current–voltage characteristics2013Ingår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 117, nr SI, s. 599-603Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Adjusting the work function of the two electrodes to the energy levels of the intrinsic active materials of an organic solar cell is crucial for a good device performance. Often, injection barriers (in combination with selective contacts blocking one charge carrier species) caused by a misaligned metal work function or extraction barriers resulting from insulating intentional or unintentional interlayers between metal and active layers, result in a decrease in fill factor seen in the extreme case in S-shaped current–voltage (J–V) characteristics. To avoid this S-kink, it is essential to identify its origin, desirably applying a simple experimental method. We propose an approach based on analyses of current–voltage data as a function of illumination intensity. A normalization of the J–V curves at the saturated photocurrent reveals distinctive features for each type of barrier. We apply the method to planar heterojunction small-molecule and bulk heterojunction polymer solar cells with oxidized metal electrode or plasma-treated active layer and explain the theory with a drift-diffusion model.

  • 540.
    Tress, Wolfgang
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan. Technical University of Dresden, Germany .
    Leo, Karl
    Technical University of Dresden, Germany .
    Riede, Moritz
    Technical University of Dresden, Germany .
    Dominating recombination mechanisms in organic solar cells based on ZnPc and C-602013Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 102, nr 16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate the dominating recombination mechanisms in bulk heterojunction solar cells, using a blend of ZnPc and C-60 as model system. Analyzing the open-circuit voltage (V-oc) as a function of illumination intensity, we find that trap-assisted recombination dominates for low light intensities, whereas at 1 sun, direct/bimolecular recombination becomes important. The recombination parameters are not significantly influenced by the blend mixing ratio and are also valid for injected charges. By changing the hole transport layer, recombination at the contact is separately identified as further mechanism reducing Voc at higher light intensities.

  • 541.
    Tress, Wolfgang
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Leo, Karl
    Technical University of Dresden, Germany .
    Riede, Moritz
    Technical University of Dresden, Germany .
    Photoconductivity as loss mechanism in organic solar cells2013Ingår i: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 7, nr 6, s. 401-405Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We observe that the reverse current under illumination in solar cells containing C60 and ZnPc is dominated by a photoshunt. This shunt, not present in the dark, causes a linear current-voltage relation under illumination showing no saturation. Although observable in bulk heterojunctions, this effect is more pronounced in the presence of a pristine C60 layer. An internal quantum efficiency larger than unity under an applied negative voltage and in the spectral range where C60 absorbs identifies charges which are injected in addition to those photogenerated. The photoshunt is also present in the power-generating region and represents a loss mechanism limiting the fill factor in particular for flat heterojunction devices.

  • 542.
    Tress, Wolfgang
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan. Swiss Federal Institute Technology EPFL, Switzerland.
    Marinova, Nevena
    Swiss Federal Institute Technology EPFL, Switzerland.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Nazeeruddin, Mohammad. K.
    Swiss Federal Institute Technology EPFL, Switzerland.
    Zakeeruddin, Shaik M.
    Swiss Federal Institute Technology EPFL, Switzerland.
    Graetzel, Michael
    Swiss Federal Institute Technology EPFL, Switzerland.
    Predicting the Open-Circuit Voltage of CH3NH3PbI3 Perovskite Solar Cells Using Electroluminescence and Photovoltaic Quantum Efficiency Spectra: the Role of Radiative and Non-Radiative Recombination2015Ingår i: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 5, nr 3, s. 1400812-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    n/a

  • 543.
    Tress, Wolfgang
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan. Swiss Federal Institute Technology EPFL, Switzerland.
    Marinova, Nevena
    Swiss Federal Institute Technology EPFL, Switzerland.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Nazeeruddin, Mohammad K.
    Swiss Federal Institute Technology EPFL, Switzerland.
    Zakeeruddin, Shaik M.
    Swiss Federal Institute Technology EPFL, Switzerland.
    Graetzel, Michael
    Swiss Federal Institute Technology EPFL, Switzerland.
    The role of the hole-transport layer in perovskite solar cells - reducing recombination and increasing absorption2014Ingår i: 2014 IEEE 40TH PHOTOVOLTAIC SPECIALIST CONFERENCE (PVSC), IEEE , 2014, s. 1563-1566Konferensbidrag (Refereegranskat)
    Abstract [en]

    The role of the hole-transport layer (HTL) in CH3NH3PbI3 perovskite solar cells is investigated. It is found that it mainly serves three purposes: First, deposited prior to the gold electrode, it avoids direct contact of the metal electrode with the meso porous TiO2-perovskite layer, and therefore increases the selectivity of the contact. This reduces recombination as evident from an increased open-circuit voltage and a higher luminescence efficiency. Second, the HTL increases the internal quantum efficiency independent of applied voltage and illumination wavelength by reducing (diffusion) losses of charges. Third, due to a smoothing of the TiO2-perovskite mesoscopic layer the HTL increases the reflectivity of the gold electrode, allowing for a second path of the light through the absorber. Both effects result in an enhancement of the short-circuit current density.

  • 544.
    Tress, Wolfgang
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan. Technical University of Dresden, Germany .
    Merten, Andre
    Technical University of Dresden, Germany .
    Furno, Mauro
    Technical University of Dresden, Germany .
    Hein, Moritz
    Technical University of Dresden, Germany .
    Leo, Karl
    Technical University of Dresden, Germany .
    Riede, Moritz
    Technical University of Dresden, Germany .
    Correlation of Absorption Profile and Fill Factor in Organic Solar Cells: The Role of Mobility Imbalance2013Ingår i: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 3, nr 5, s. 631-638Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate the role of the spatial absorption profile within bulk heterojunction small molecule solar cells comprising a 50 nm ZnPc:C60 active layer. Exploiting interference effects the absorption profile is varied by both the illumination wavelength and the thickness of an optical spacer layer adjacent to the reflecting electrode. The fill factor under 1 sun illumination is observed to change from 43 to 49% depending on the absorption profile which approximately equals the charge-carrier generation profile. It is shown by varying the mixing ratio between ZnPc and C60 that the importance of the generation profile is correlated with the imbalance of mobilities. Therefore, it is concluded that non-geminate recombination is the dominating loss mechanism in these devices. Numerical drift-diffusion simulations reproduce the experimental observations showing that charge carrier extraction is more efficient if charge carriers are generated close to the contact collecting the less mobile charge carrier type. Furthermore, this effect can explain the dependence of the internal quantum efficiency measured at short circuit on wavelength and implies that the spectral mismatch for a given solar simulator and device depends on the applied voltage.

  • 545.
    Tvingstedt, Kristofer
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Light Trapping and Alternative Electrodes for Organic Photovoltaic Devices2007Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Organic materials, such as conjugated polymers, have emerged as a promising alternative for the production of inexpensive and flexible photovoltaic cells. As conjugated polymers are soluble, liquid based printing techniques enable production on large scale to a price much lower than that for inorganic based solar cells. Present day state of the art conjugated polymer photovoltaic cells are comprised by blends of a semiconducting polymer and a soluble derivative of fullerene molecules. Such bulk heterojunction solar cells now show power conversion efficiencies of up to 4-6%. The quantum efficiency of thin film organic solar cells is however still limited by several processes, of which the most prominent limitations are the comparatively low mobility and the high level of charge recombination. Hence organic cells do not yet perform as well as their more expensive inorganic counterparts. In order to overcome this present drawback of conjugated polymer photovoltaics, efforts are continuously devoted to developing materials or devices with increased absorption or with better charge carrier transporting properties. The latter can be facilitated by increasing the mobility of the pure material or by introducing beneficial morphology to prevent carrier recombination. Minimizing the active layer film thickness is an alternative route to collect more of the generated free charge carriers. However, a minimum film thickness is always required for sufficient photon absorption.

    A further limitation for low cost large scale production has been the dependence on expensive transparent electrodes such as indium tin oxide. The development of cheaper electrodes compatible with fast processing is therefore of high importance.

    The primary aim of this work has been to increase the absorption in solar cells made from thin films of organic materials. Device construction, deploying new geometries, and evaluation of different methods to provide for light trapping and photon recycling have been strived for. Different routes to construct and incorporate light trapping structures that enable higher photon absorption in a thinner film are presented. By recycling the reflected photons and enhancing the optical path length within a thinner cell, the absorption rate, as well as the collection of more charge carriers, is provided for. Attempts have been performed by utilizing a range of different structures with feature sizes ranging from nanometers up to centimeters. Surface plasmons, Lambertian scatterers, micro lenses, tandem cells as well as larger folded cell structures have been evaluated. Naturally, some of these methods have turned out to be more successful than others. From this work it can nevertheless be concluded that proper light trapping, in thin films of organic materials for photovoltaic energy conversion, is a technique capable of improving the cell performance.

    In addition to the study of light trapping, two new alternative electrodes for polymer photovoltaic devices are suggested and evaluated.

    Delarbeten
    1. Light Confinement in Thin Film Organic Photovoltaic cells
    Öppna denna publikation i ny flik eller fönster >>Light Confinement in Thin Film Organic Photovoltaic cells
    2006 (Engelska)Ingår i: Photonics Europe, Strasbourg, 2006, Vol. 6197Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Microstructuring of polymer surfaces on optical spacers allows formation of reflective light traps. Such flexible reflectors can be combined with flexible polymer solar cells. We have demonstrated enhanced absorption using Lambertian and regular light reflectors, demonstrated via luminescence from fluorescent layers. Such light traps are suitable to use in combination with polymer solar cells incorporating transparent electrodes. The possibility to enhance the concentration of excited states and photogenerated charges through light trapping also helps to increase charge carrier mobility. These experimental results indicate that light confinement may be an alternative approach for boosting the efficiency of thin film conjugated polymer photovoltaics.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-17206 (URN)10.1117/12.662794 (DOI)
    Tillgänglig från: 2009-03-10 Skapad: 2009-03-10 Senast uppdaterad: 2009-06-05Bibliografiskt granskad
    2. Surface plasmon increased absorption in polymer photovoltaic cells
    Öppna denna publikation i ny flik eller fönster >>Surface plasmon increased absorption in polymer photovoltaic cells
    Visa övriga...
    2007 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, nr 11, s. 113514 -Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The authors demonstrate the triggering of surface plasmons at the interface of a metal grating and a photovoltaic bulk heterojunction blend of alternating polyfluorenes and a fullerene derivative. An increased absorption originating from surface plasmon resonances is confirmed by experimental reflection studies and theoretical modeling. Plasmonic resonances are further confirmed to influence the extracted photocurrent from devices. More current is generated at the wavelength position of the plasmon resonance peak. High conductivity polymer electrodes are used to build inverted sandwich structures with top anode and bottom metal grating, facilitating for triggering and characterization of the surface plasmon effects.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14621 (URN)10.1063/1.2782910 (DOI)
    Tillgänglig från: 2007-08-30 Skapad: 2007-08-30 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    3. Trapping light with micro lenses in thin film organic photovoltaic cells
    Öppna denna publikation i ny flik eller fönster >>Trapping light with micro lenses in thin film organic photovoltaic cells
    2008 (Engelska)Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 16, nr 26, s. 21608-21615Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We demonstrate a novel light trapping configuration based on an array of micro lenses in conjunction with a self aligned array of micro apertures located in a highly reflecting mirror. When locating the light trapping element, that displays strong directional asymmetric transmission, in front of thin film organic photovoltaic cells, an increase in cell absorption is obtained. By recycling reflected photons that otherwise would be lost, thinner films with more beneficial electrical properties can effectively be deployed. The light trapping element enhances the absorption rate of the solar cell and increases the photocurrent by as much as 25%.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-16406 (URN)10.1364/OE.16.021608 (DOI)
    Anmärkning
    On the day of the defence date the status of this article was: In Manuscript.Tillgänglig från: 2009-01-23 Skapad: 2009-01-23 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    4. Folded reflective tandem polymer solar cell doubles efficiency
    Öppna denna publikation i ny flik eller fönster >>Folded reflective tandem polymer solar cell doubles efficiency
    2007 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, nr 12, s. 123514-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Conjugated polymers are promising materials for the production of inexpensive and flexible photovoltaic cells. Organic materials display tunable optical absorption within a large spectral range. This enables the construction of organic tandem photovoltaic cells. The authors here demonstrate a reflective tandem cell where single cells are reflecting the nonabsorbed light upon another adjacent cell. By folding two planar but spectrally different cells toward each other, spectral broadening and light trapping are combined to give an enhancement of power conversion efficiency of a factor of 1.8±0.3.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-17204 (URN)10.1063/1.2789393 (DOI)
    Tillgänglig från: 2009-03-10 Skapad: 2009-03-10 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    5. Optical modeling of a folded organic solar cell
    Öppna denna publikation i ny flik eller fönster >>Optical modeling of a folded organic solar cell
    2008 (Engelska)Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, nr 9, s. 094520-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The optical behavior of a reflective tandem solar cell (V cell) is modeled by means of finite element method (FEM) simulations. The absorption of solar light in the active material as well as in both electrode layers is calculated. The FEM solves the electromagnetic wave equation on the entire defined geometry, resulting in the consideration of interference effects, as well as effects of refraction and reflection. Both single cells and tandem cells are modeled and confirmed to be in accordance with reflectance measurements. Energy dissipation in the active layers is studied as a function of layer thickness and folding angle, and the simulations clearly display the advantage of the light trapping feature of folded cells. This is especially prominent in cells with thinner active layers, where folding induces absorption in the active layer equivalent to that of much thicker cells.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-17205 (URN)10.1063/1.2917062 (DOI)
    Tillgänglig från: 2009-03-10 Skapad: 2009-03-10 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    6. Transparent polymer cathode for organic photovoltaic devices
    Öppna denna publikation i ny flik eller fönster >>Transparent polymer cathode for organic photovoltaic devices
    Visa övriga...
    2006 (Engelska)Ingår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 156, nr 16-17, s. 1102-1107Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We demonstrate a prototype solar cell with a transparent polymer cathode, and indium-tin-oxide (ITO)/poly (3, 4-ethylene dioxythiophene)-poly (styrene sulphonate) (PEDOT:PSS) anode. As an active layer, thin film of a bulk heterojunction of polyfluorene copolymer poly[2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4′,7′-di-2thienyl-2′,1′3′-benzothiadiazole)] (APFO-3) and an electron acceptor molecule [6] and [6]-phenyl-C61-butyric acid methyl ester (PCBM) (1:4 wt.) was sandwiched between the two transparent polymer electrodes. The cathode is another form of PEDOT formed by vapor phase polymerised PEDOT (VPP PEDOT) of conductivity 102–103 S/cm. The cathode is supported on an elastomeric substrate, and forms a conformal contact to the APFO-3/PCBM blend. Transparent solar cells are useful for building multilayer and tandem solar cells.

    Nyckelord
    PEDOT; Vapor phase polymerization; VPP–PEDOT; Soft contact lamination; All-plastic solar cell; Ultraviolet photoelectron spectroscopy
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14223 (URN)10.1016/j.synthmet.2006.07.006 (DOI)
    Tillgänglig från: 2007-01-15 Skapad: 2007-01-15 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    7. Electrode grids for ITO-free organic photovoltaic devices
    Öppna denna publikation i ny flik eller fönster >>Electrode grids for ITO-free organic photovoltaic devices
    2007 (Engelska)Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 19, nr 19, s. 2893-2897Artikel i tidskrift (Refereegranskat) Published
    Ort, förlag, år, upplaga, sidor
    Wiley InterScience, 2007
    Nyckelord
    Conjugated polymers, Electrodes, Organic electronics, Photovoltaic devices, Solar cells
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-17203 (URN)10.1002/adma.200602561 (DOI)
    Tillgänglig från: 2009-03-10 Skapad: 2009-03-10 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
  • 546.
    Tvingstedt, Kristofer
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Andersson, Viktor
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Folded reflective tandem polymer solar cell doubles efficiency2007Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, nr 12, s. 123514-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Conjugated polymers are promising materials for the production of inexpensive and flexible photovoltaic cells. Organic materials display tunable optical absorption within a large spectral range. This enables the construction of organic tandem photovoltaic cells. The authors here demonstrate a reflective tandem cell where single cells are reflecting the nonabsorbed light upon another adjacent cell. By folding two planar but spectrally different cells toward each other, spectral broadening and light trapping are combined to give an enhancement of power conversion efficiency of a factor of 1.8±0.3.

  • 547.
    Tvingstedt, Kristofer
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Dal Zilio, Simone
    CNR-Istituto Nazionale per la Fisica della Materia, Laboratorio Nazionale TASC Area Science Park - Basovizza S.S.14 I-34012 (TS), Italy.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Tormen , Massimo
    CNR-Istituto Nazionale per la Fisica della Materia, Laboratorio Nazionale TASC Area Science Park - Basovizza S.S.14 I-34012 (TS), Italy.
    Trapping light with micro lenses in thin film organic photovoltaic cells2008Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 16, nr 26, s. 21608-21615Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrate a novel light trapping configuration based on an array of micro lenses in conjunction with a self aligned array of micro apertures located in a highly reflecting mirror. When locating the light trapping element, that displays strong directional asymmetric transmission, in front of thin film organic photovoltaic cells, an increase in cell absorption is obtained. By recycling reflected photons that otherwise would be lost, thinner films with more beneficial electrical properties can effectively be deployed. The light trapping element enhances the absorption rate of the solar cell and increases the photocurrent by as much as 25%.

  • 548.
    Tvingstedt, Kristofer
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Electrode grids for ITO-free organic photovoltaic devices2007Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 19, nr 19, s. 2893-2897Artikel i tidskrift (Refereegranskat)
  • 549.
    Tvingstedt, Kristofer
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Submicron gratings for conjugated polymer photonics2004Ingår i: Optik i Sverige - Svenska Optiksällskapet,2004, 2004Konferensbidrag (Övrigt vetenskapligt)
  • 550.
    Tvingstedt, Kristofer
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Rahachou, Aliaksandr
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Persson, Nils-Krister
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Zozoulenko, Igor V.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Surface plasmon increased absorption in polymer photovoltaic cells2007Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, nr 11, s. 113514 -Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The authors demonstrate the triggering of surface plasmons at the interface of a metal grating and a photovoltaic bulk heterojunction blend of alternating polyfluorenes and a fullerene derivative. An increased absorption originating from surface plasmon resonances is confirmed by experimental reflection studies and theoretical modeling. Plasmonic resonances are further confirmed to influence the extracted photocurrent from devices. More current is generated at the wavelength position of the plasmon resonance peak. High conductivity polymer electrodes are used to build inverted sandwich structures with top anode and bottom metal grating, facilitating for triggering and characterization of the surface plasmon effects.

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