High-Performance Fluorinated Fused-Ring Electron Acceptor with 3D Stacking and Exciton/Charge Transport

Shuixing Dai, Jiadong Zhou, Sreelakshmi Chandrabose, Yanjun Shi, Guangchao Han, Kai Chen, Jingming Xin, Kuan Liu, Zhenyu Chen, Zengqi Xie, Wei Ma, Yuanping Yi, Lang Jiang, Justin M. Hodgkiss, Xiaowei Zhan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

76 Citations (Scopus)

Abstract

A new fluorinated electron acceptor (FINIC) based on 6,6,12,12-tetrakis(3-fluoro-4-hexylphenyl)-indacenobis(dithieno[3,2-b;2′,3′-d]thiophene) as the electron-donating central core and 5,6-difluoro-3-(1,1-dicyanomethylene)-1-indanone as the electron-deficient end groups is rationally designed and synthesized. FINIC shows similar absorption profile in dilute solution to the nonfluorinated analogue INIC. However, compared with INIC, FINIC film shows red-shifted absorption, down-shifted frontier molecular orbital energy levels, enhanced crystallinity, and more ordered molecular packing. Single-crystal structure data show that FINIC molecules pack into closer 3D “network” motif through H-bonding and π–π interaction, while INIC molecules pack into incompact “honeycomb” motif through only π–π stacking. Theoretical calculations reveal that FINIC has stronger electronic coupling and more molecular interactions than INIC. FINIC has higher electron mobilities in both horizontal and vertical directions than INIC. Moreover, FINIC and INIC support efficient 3D exciton transport. PBD-SF/FINIC blend has a larger driving force for exciton splitting, more efficient charge transfer and photoinduced charge generation. Finally, the organic solar cells based on PBD-SF/FINIC blend yield power conversion efficiency of 14.0%, far exceeding that of the PBD-SF/INIC-based devices (5.1%).

Original languageEnglish
Article numberArticle number 2000645
JournalAdvanced Materials
Volume32
Issue number21
DOIs
Publication statusPublished - 1 May 2020

Keywords

  • 3D stacking
  • fluorination
  • fused-ring electron acceptors
  • nonfullerene acceptors
  • polymer solar cells

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this