Effect of Terminal Electron-Withdrawing Group on the Photovoltaic Performance of Asymmetric Fused-Ring Electron Acceptors

Chao Li, Guangkai Lu, Hwa Sook Ryu, Xiaobo Sun, Han Young Woo, Yanming Sun

Research output: Contribution to journalArticlepeer-review

Abstract

The terminal electron-withdrawing group is thought to strongly influence π-πstacking interactions and thereby the charge transport properties of fused-ring electron acceptors (FREAs). In this work, we designed and synthesized three asymmetric/symmetric small molecule FREAs (LC301, LC302, and LC303), in which three electron-withdrawing functional groups with different polarities (phenyl-fused indanone < thienyl-fused indanone < F-modified phenyl-fused indanone) were selected as the terminal groups. Photophysical properties, electrochemistry, charge transport, and crystalline properties of the materials were studied to investigate the effect of electron-withdrawing abilities of the terminal groups on the properties of FREAs. Starting from the symmetric LC302 (two thienyl-fused indanone terminal groups), we have found that by simply replacing only one thienyl-fused indanone terminal group in symmetric LC302 with one difluorinated phenyl-fused indanone terminal group, the asymmetric LC301-based organic solar cells (OSCs) can yield a high power conversion efficiency (PCE) of 17.21% and a promising fill factor (FF) of 78.1%, which are higher than those of symmetric LC302-based OSCs (PCE = 15.18%, FF = 73.3%) and the asymmetric LC303-based OSCs bearing one thienyl-fused indanone terminal group and one nonfluorinated phenyl-fused indanone terminal group (PCE = 14.28%, FF = 70.3%). The results indicate that the rational selection of terminal groups with different electron-withdrawing capabilities is highly desirable for designing high-performance asymmetric FREAs.

Original languageEnglish
Pages (from-to)43207-43214
Number of pages8
JournalACS Applied Materials and Interfaces
Volume14
Issue number38
DOIs
Publication statusPublished - 2022 Sep 28

Keywords

  • asymmetric small molecule
  • electron-withdrawing group
  • fused-ring electron acceptor
  • organic solar cells
  • terminal group

ASJC Scopus subject areas

  • Materials Science(all)

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