Journal article

Sub-picosecond charge-transfer at near-zero driving force in polymer:non-fullerene acceptor blends and bilayers.

  • Zhong Y Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland.
  • Causa' M Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland.
  • Moore GJ Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland.
  • Krauspe P Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland.
  • Xiao B Chinese Academy of Sciences (CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China.
  • Günther F Instituto de Física de São Carlos (IFSC), Universidade de São Paulo (USP), Av. Trabalhador saocarlense, 400, CEP, 13560-970, São Carlos, Brazil.
  • Kublitski J Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics Technische Universität Dresden, Nöthnitzer Str. 61, 01187, Dresden, Germany.
  • Shivhare R Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics Technische Universität Dresden, Nöthnitzer Str. 61, 01187, Dresden, Germany.
  • Benduhn J Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics Technische Universität Dresden, Nöthnitzer Str. 61, 01187, Dresden, Germany.
  • BarOr E Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany.
  • Mukherjee S Material Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA.
  • Yallum KM Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland.
  • Réhault J Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland.
  • Mannsfeld SCB Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics Technische Universität Dresden, Nöthnitzer Str. 61, 01187, Dresden, Germany.
  • Neher D Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany.
  • Richter LJ Material Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA.
  • DeLongchamp DM Material Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA.
  • Ortmann F Center for Advancing Electronics Dresden, Technische Universität Dresden, Helmholtzstr. 18, 01062, Dresden, Germany.
  • Vandewal K Institute for Materials Research (IMO-IMOMEC), Hasselt University, Wetenschapspark 1, 3590, Diepenbeek, Belgium.
  • Zhou E Chinese Academy of Sciences (CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China. zhouej@nanoctr.cn.
  • Banerji N Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland. natalie.banerji@dcb.unibe.ch.
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  • 2020-02-13
Published in:
  • Nature communications. - 2020
English Organic photovoltaics based on non-fullerene acceptors (NFAs) show record efficiency of 16 to 17% and increased photovoltage owing to the low driving force for interfacial charge-transfer. However, the low driving force potentially slows down charge generation, leading to a tradeoff between voltage and current. Here, we disentangle the intrinsic charge-transfer rates from morphology-dependent exciton diffusion for a series of polymer:NFA systems. Moreover, we establish the influence of the interfacial energetics on the electron and hole transfer rates separately. We demonstrate that charge-transfer timescales remain at a few hundred femtoseconds even at near-zero driving force, which is consistent with the rates predicted by Marcus theory in the normal region, at moderate electronic coupling and at low re-organization energy. Thus, in the design of highly efficient devices, the energy offset at the donor:acceptor interface can be minimized without jeopardizing the charge-transfer rate and without concerns about a current-voltage tradeoff.
Language
  • English
Open access status
gold
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Persistent URL
https://sonar.ch/global/documents/185127
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