A New Wide Bandgap Donor Polymer for Efficient Nonfullerene Organic Solar Cells with a Large Open-Circuit Voltage

Yumin Tang, Huiliang Sun, Ziang Wu, Yujie Zhang, Guangye Zhang, Mengyao Su, Xin Zhou, Xia Wu, Weipeng Sun, Xianhe Zhang, Bin Liu, Wei Chen, Qiaogan Liao, Han Young Woo, Xugang Guo

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Significant progress has been made in nonfullerene small molecule acceptors (NF-SMAs) that leads to a consistent increase of power conversion efficiency (PCE) of nonfullerene organic solar cells (NF-OSCs). To achieve better compatibility with high-performance NF-SMAs, the direction of molecular design for donor polymers is toward wide bandgap (WBG), tailored properties, and preferentially ecofriendly processability for device fabrication. Here, a weak acceptor unit, methyl 2,5-dibromo-4-fluorothiophene-3-carboxylate (FE-T), is synthesized and copolymerized with benzo[1,2-b:4,5-b′]dithiophene (BDT) to afford a series of nonhalogenated solvent processable WBG polymers P1-P3 with a distinct side chain on FE-T. The incorporation of FE-T leads to polymers with a deep highest occupied molecular orbital (HOMO) level of −5.60−5.70 eV, a complementary absorption to NF-SMAs, and a planar molecular conformation. When combined with the narrow bandgap acceptor ITIC-Th, the solar cell based on P1 with the shortest methyl chain on FE-T achieves a PCE of 11.39% with a large Voc of 1.01 V and a Jsc of 17.89 mA cm−2. Moreover, a PCE of 12.11% is attained for ternary cells based on WBG P1, narrow bandgap PTB7-Th, and acceptor IEICO-4F. These results demonstrate that the new FE-T is a highly promising acceptor unit to construct WBG polymers for efficient NF-OSCs.

Original languageEnglish
Article number1901773
JournalAdvanced Science
Volume6
Issue number21
DOIs
Publication statusPublished - 2019 Nov 1

Keywords

  • complementary absorption
  • donor polymers
  • nonfullerene organic solar cells
  • nonhalogenated solvents
  • wide bandgap

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Chemical Engineering(all)
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)
  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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