Reducing energy loss via tuning energy levels of polymer acceptors for efficient all-polymer solar cells

Research output: Contribution to journalArticle

Abstract

The open-circuit voltage (Voc) of all-polymer solar cells (all-PSCs) is typically lower than 0.9 V even for the most efficient ones. Large energy loss is the main reason for limiting Voc and efficiency of all-PSCs. Herein, through materials design using electron deficient building blocks based on bithiophene imides, the lowest unoccupied molecular orbital (LUMO) energy levels of polymer acceptors can be effectively tuned, which resulted in a reduced energy loss induced by charge generation and recombination loss due to the suppressed charge-transfer (CT) state absorption. Despite a negligible driving force, all-PSC based on the polymer donor and acceptor combination with well-aligned energy levels exhibited efficient charge transfer and achieved an external quantum efficiency over 10% while maintaining a large Voc of 1.02 V, leading to a 9.21% efficiency. Through various spectroscopy approaches, this work sheds light on the mechanism of energy loss in all-PSCs, which paves an avenue to achieving efficient all-PSCs with large Voc and drives the further development of all-PSCs.

Details

Authors
  • Huiliang Sun
  • Bin Liu
  • Jianwei Yu
  • Xianshao Zou
  • Guangye Zhang
  • Yujie Zhang
  • Wei Zhang
  • Mengyao Su
  • Qunping Fan
  • Kun Yang
  • Jianhua Chen
  • He Yan
  • Feng Gao
  • Xugang Guo
Organisations
External organisations
  • Southern University of Science and Technology
  • Hong Kong University of Science and Technology
  • Peking University
  • Linköping University
  • Guangzhou University
  • Chalmers University of Technology
  • eFlexPV Limited
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Polymer Chemistry
  • Materials Chemistry

Keywords

  • all-polymer solar cells, energy level modulation, energy loss, photovoltage, polymer acceptors
Original languageEnglish
JournalScience China Chemistry
Publication statusE-pub ahead of print - 2020 Jul 30
Publication categoryResearch
Peer-reviewedYes