Side‐Chain Engineering for Enhancing the Molecular Rigidity and Photovoltaic Performance of Noncovalently Fused‐Ring Electron Acceptors

作者：Zhang Xin; Li Congqi; Qin Linqing; Chen Hao; Yu Jianwei; Wei Yanan; Liu Xingzheng; Zhang Jianqi; Wei Zhixiang; Gao Feng; Peng Qian; Huang Hui

来源：Angewandte Chemie, 2021, 133(32): 17861-17866.

DOI：10.1002/ange.202106753

• molecular rigidity
• noncovalently fused-ring electron acceptors
• organic solar cells
• terminal side chains

Side‐chain engineering is an effective strategy to regulate the solubility and packing behavior of organic materials. Recently, a unique strategy, so‐called terminal side‐chain (T‐SC) engineering, has attracted much attention in the field of organic solar cells (OSCs), but there is a lack of deep understanding of the mechanism. Herein, a new noncovalently fused‐ring electron acceptor (NFREA) containing two T‐SCs (NoCA‐5) was designed and synthesized. Introduction of T‐SCs can enhance molecular rigidity and intermolecular π–π stacking, which is confirmed by the smaller Stokes shift value, lower reorganization free energy, and shorter π–π stacking distance in comparison to NoCA‐1. Hence, the NoCA‐5‐based device exhibits a record power conversion efficiency (PCE) of 14.82?% in labs and a certified PCE of 14.5?%, resulting from a high electron mobility, a short charge‐extraction time, a small Urbach energy (Eu), and a favorable phase separation.

• 单位
  中国科学院; 中国科学院大学