Insertion of chlorine atoms onto π-bridges of conjugated polymer enables improved photovoltaic performance

Linglong Ye, Yuanpeng Xie, Kangkang Weng, Hwa Sook Ryu, Chao Li, Yunhao Cai, Huiting Fu, Donghui Wei, Han Young Woo, Songting Tan, Yanming Sun

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

π-Bridges play a crucially important role in determining the optical absorption, bandgap and energy levels of donor-π-acceptor-π type conjugated polymers. In this contribution, a new polymer donor named PBT1-C-2Cl is synthesized by inserting the chlorine atoms onto π-bridges of the polymer PBT1-C. The introduction of chlorine atoms enables PBT1-C-2Cl with a lower highest occupied molecular orbital energy level and enhanced crystallinity than those of PBT1-C due to the high electronegativity and big atomic radius of chloride atom. When PBT1-C-2Cl is blended with the non-fullerene acceptor IT-4F, a high power conversion efficiency (PCE) of 12.7%, an open-circuit voltage (V oc ) of 0.85 V and an impressive fill factor (FF) of 76.0% are achieved, which are all higher than those of PBT1-C:IT-4F based devices (PCE = 10.9%, V oc = 0.79 V and FF = 70.5%). The enhanced charge dissociation, efficient charge transport and reduced charge recombination account for the improved photovoltaic performance of PBT1-C-2Cl: IT-4F devices. The results indicate that inserting chlorine atoms onto π-bridges is a rational strategy for the synthesis of high-performance donor-π-acceptor-π type conjugated polymer donors.

Original languageEnglish
Pages (from-to)220-226
Number of pages7
JournalNano Energy
Volume58
DOIs
Publication statusPublished - 2019 Apr 1

Keywords

  • Chlorinated thiophene
  • Conjugated polymers
  • Organic solar cells
  • Power conversion efficiency
  • π-bridge

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Electrical and Electronic Engineering

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