iScience (Jul 2019)

Isomer-free: Precise Positioning of Chlorine-Induced Interpenetrating Charge Transfer for Elevated Solar Conversion

  • Hanjian Lai,
  • Hui Chen,
  • Jiadong Zhou,
  • Jianfei Qu,
  • Pengjie Chao,
  • Tao Liu,
  • Xiaoyong Chang,
  • Nan Zheng,
  • Zengqi Xie,
  • Feng He

Journal volume & issue
Vol. 17
pp. 302 – 314

Abstract

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Summary: The influence caused by the position of the chlorine atom on end groups of two non-fullerene acceptors (ITIC-2Cl-δ and ITIC-2Cl-γ) was intensely investigated. The single-crystal structures show that ITIC-2Cl-γ has a better molecular planarity and closer π-π interaction distance. More importantly, a 3D rectangle-like interpenetrating network is formed in ITIC-2Cl-γ and is beneficial to rapid charge transfer along multiple directions, whereas only a linear stacked structure could be observed in ITIC-2Cl-δ. The two acceptor-based solar cells show power conversion efficiencies (PCEs) over 11%, higher than that of the ITIC-2Cl-m-based device (10.85%). An excellent PCE of 13.03% is obtained by the ITIC-2Cl-γ-based device. In addition, the ITIC-2Cl-γ-based device also shows the best device stability. This study indicates that chlorine positioning has a great impact on the acceptors; more importantly, the 3D network structure may be a promising strategy for non-fullerene acceptors to improve the PCE and stability of organic solar cells. : Energy Storage; Chemical Synthesis; Materials Characterization Techniques Subject Areas: Energy Storage, Chemical Synthesis, Materials Characterization Techniques