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Insight into the Origin of Trapping in Polymer/Fullerene Blends with a Systematic Alteration of the Fullerene to Higher Adducts.
Marin-Beloqui, Jose; Zhang, Guanran; Guo, Junjun; Shaikh, Jordan; Wohrer, Thibaut; Hosseini, Seyed Mehrdad; Sun, Bowen; Shipp, James; Auty, Alexander J; Chekulaev, Dimitri; Ye, Jun; Chin, Yi-Chun; Sullivan, Michael B; Mozer, Attila J; Kim, Ji-Seon; Shoaee, Safa; Clarke, Tracey M.
Afiliação
  • Marin-Beloqui J; Department of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, United Kingdom.
  • Zhang G; ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong, North Wollongong, NSW 2500, Australia.
  • Guo J; Department of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, United Kingdom.
  • Shaikh J; Department of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, United Kingdom.
  • Wohrer T; Department of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, United Kingdom.
  • Hosseini SM; Institute of High Performance Computing ASTAR, Singapore 138632, Singapore.
  • Sun B; Optoelectronics of Disordered Semiconductors, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24-25, Potsdam-Golm 14476, Germany.
  • Shipp J; Optoelectronics of Disordered Semiconductors, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24-25, Potsdam-Golm 14476, Germany.
  • Auty AJ; Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom.
  • Chekulaev D; Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom.
  • Ye J; Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom.
  • Chin YC; Institute of High Performance Computing ASTAR, Singapore 138632, Singapore.
  • Sullivan MB; Department of Physics and Centre for Processable Electronics, Imperial College London, London SW7 2AZ, United Kingdom.
  • Mozer AJ; Institute of High Performance Computing ASTAR, Singapore 138632, Singapore.
  • Kim JS; ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong, North Wollongong, NSW 2500, Australia.
  • Shoaee S; Department of Physics and Centre for Processable Electronics, Imperial College London, London SW7 2AZ, United Kingdom.
  • Clarke TM; Optoelectronics of Disordered Semiconductors, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24-25, Potsdam-Golm 14476, Germany.
J Phys Chem C Nanomater Interfaces ; 126(5): 2708-2719, 2022 Feb 10.
Article em En | MEDLINE | ID: mdl-35573707
The bimolecular recombination characteristics of conjugated polymer poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,5-bis 3-tetradecylthiophen-2-yl thiazolo 5,4-d thiazole)-2,5diyl] (PDTSiTTz) blended with the fullerene series PC60BM, ICMA, ICBA, and ICTA have been investigated using microsecond and femtosecond transient absorption spectroscopy, in conjunction with electroluminescence measurements and ambient photoemission spectroscopy. The non-Langevin polymer PDTSiTTz allows an inspection of intrinsic bimolecular recombination rates uninhibited by diffusion, while the low oscillator strengths of fullerenes allow polymer features to dominate, and we compare our results to those of the well-known polymer Si-PCPDTBT. Using µs-TAS, we have shown that the trap-limited decay dynamics of the PDTSiTTz polaron becomes progressively slower across the fullerene series, while those of Si-PCPDTBT are invariant. Electroluminescence measurements showed an unusual double peak in pristine PDTSiTTz, attributed to a low energy intragap charge transfer state, likely interchain in nature. Furthermore, while the pristine PDTSiTTz showed a broad, low-intensity density of states, the ICBA and ICTA blends presented a virtually identical DOS to Si-PCPDTBT and its blends. This has been attributed to a shift from a delocalized, interchain highest occupied molecular orbital (HOMO) in the pristine material to a dithienosilole-centered HOMO in the blends, likely a result of the bulky fullerenes increasing interchain separation. This HOMO localization had a side effect of progressively shifting the polymer HOMO to shallower energies, which was correlated with the observed decrease in bimolecular recombination rate and increased "trap" depth. However, since the density of tail states remained the same, this suggests that the traditional viewpoint of "trapping" being dominated by tail states may not encompass the full picture and that the breadth of the DOS may also have a strong influence on bimolecular recombination.

Texto completo: 1 Base de dados: MEDLINE Idioma: En Ano de publicação: 2022 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Idioma: En Ano de publicação: 2022 Tipo de documento: Article