Traps and transport resistance are the next frontiers for stable non-fullerene acceptor solar cells

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Christopher Wöpke - , Technische Universität Chemnitz Institut für Physik (Author)
  • Clemens Göhler - , Technische Universität Chemnitz Institut für Physik (Author)
  • Maria Saladina - , Technische Universität Chemnitz Institut für Physik (Author)
  • Xiaoyan Du - , Friedrich-Alexander University Erlangen-Nürnberg (Author)
  • Li Nian - , Friedrich-Alexander University Erlangen-Nürnberg, South China Normal University (Author)
  • Christopher Greve - , University of Bayreuth (Author)
  • Chenhui Zhu - , United States Department of Energy (Author)
  • Kaila M. Yallum - , University of Bern (Author)
  • Yvonne J. Hofstetter - , Chair of Emerging Electronic Technologies (Faculty of Physics), Chair of Emerging Electronic Technologies (cfaed) (Author)
  • David Becker-Koch - , Chair of Emerging Electronic Technologies (cfaed), Chair of Emerging Electronic Technologies (Faculty of Physics) (Author)
  • Ning Li - , Friedrich-Alexander University Erlangen-Nürnberg, South China University of Technology (Author)
  • Thomas Heumüller - , Friedrich-Alexander University Erlangen-Nürnberg (Author)
  • Ilya Milekhin - , Technische Universität Chemnitz Institut für Physik (Author)
  • Dietrich R.T. Zahn - , Technische Universität Chemnitz Institut für Physik (Author)
  • Christoph J. Brabec - , Friedrich-Alexander University Erlangen-Nürnberg (Author)
  • Natalie Banerji - , University of Bern (Author)
  • Yana Vaynzof - , Chair of Emerging Electronic Technologies (Faculty of Physics), Chair of Emerging Electronic Technologies (cfaed) (Author)
  • Eva M. Herzig - , University of Bayreuth (Author)
  • Roderick C.I. MacKenzie - , Durham University (Author)
  • Carsten Deibel - , Technische Universität Chemnitz Institut für Physik (Author)

Abstract

Stability is one of the most important challenges facing material research for organic solar cells (OSC) on their path to further commercialization. In the high-performance material system PM6:Y6 studied here, we investigate degradation mechanisms of inverted photovoltaic devices. We have identified two distinct degradation pathways: one requires the presence of both illumination and oxygen and features a short-circuit current reduction, the other one is induced thermally and marked by severe losses of open-circuit voltage and fill factor. We focus our investigation on the thermally accelerated degradation. Our findings show that bulk material properties and interfaces remain remarkably stable, however, aging-induced defect state formation in the active layer remains the primary cause of thermal degradation. The increased trap density leads to higher non-radiative recombination, which limits the open-circuit voltage and lowers the charge carrier mobility in the photoactive layer. Furthermore, we find the trap-induced transport resistance to be the major reason for the drop in fill factor. Our results suggest that device lifetimes could be significantly increased by marginally suppressing trap formation, leading to a bright future for OSC.

Details

Original languageEnglish
Article number3786
Pages (from-to)1-8
Number of pages8
JournalNature communications
Volume13
Issue number1
Publication statusPublished - Dec 2022
Peer-reviewedYes

Keywords