Selenium-containing two-dimensional conjugated fused-ring electron acceptors for enhanced crystal packing, charge transport, and photovoltaic performance

Shi Sheng Wan, Qiaoqiao Zhao, Zhao Jiang, Gui Zhou Yuan, Lu Yan, Hwa Sook Ryu, Asif Mahmood, Yan Qiang Liu, Heng Li, Han Young Woo, Feng He, Jin Liang Wang

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Although two-dimensional fused-ring electron acceptors (FREAs) have recently attracted increasing attention, designing highly efficient two-dimensional FREAs with a new heterocycle-based two-dimensional central core for further development is still a great challenge. Herein, two chlorinated two-dimensional fused-ring electron acceptors (namelyC8T-BDT4ClandC8T-BDSe4Cl) were synthesized for polymer solar cells, featuring with the two-dimensional conjugated central donor units by alkylthienyl-substituted benzo[1,2-b:4,5-b′]dithiophene (BDT) and benzo[1,2-b:4,5-b′]diselenophene (BDSe), respectively. Compared withC8T-BDT4Cl,C8T-BDSe4Clexhibits a red-shifted absorption spectrum and a narrower optical bandgap. Moreover, we first studied the single crystals of such two-dimensional conjugated FREAs and the crystallographic analysis indicates that both acceptors presented 3D network packing with three independent molecular conformations, butC8T-BDSe4Clexhibits more enhanced multiple intermolecular interactions with slightly shorter π-π interaction distances. AC8T-BDSe4Cl:PM6-based blend film exhibited a more favorable morphology with better face-on intermolecular packing with a longer coherent length and more suitable phase separation, resulting in more efficient charge separation, transport, and collection. Consequently, benefiting from the above-mentioned merits, polymer solar cells (PSCs) based onC8T-BDSe4Cl:PM6presented a much higher power conversion efficiency (PCE) of 13.5% with higherJscthan that of sulfur-containing analogue-basedC8T-BDT4Cl:PM6(12.2%). These results indicate a unique application prospect of the selenium-substituted FREAs and demonstrate that combination of the two-dimensional conjugated central core and selenium-substituted in the central electron-rich position strategy is an effective approach to improve theJscvalue and PCE of two-dimensional FREA-based PSCs.

Original languageEnglish
Pages (from-to)15665-15677
Number of pages13
JournalJournal of Materials Chemistry A
Volume9
Issue number28
DOIs
Publication statusPublished - 2021 Jul 28

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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