A Near-infrared Non-fullerene Acceptor with Thienopyrrole-expanded Benzo[1,2-b:4,5-b']dithiophene Core for Polymer Solar Cells

• 作者: Zhen Chen Shan-Shan Ma Kai Zhang Zhi-Cheng Hu Qing-Wu Yin Fei Huang Yong Cao
• 来源期刊: 高分子科学（英文版）
• 年，卷（期）: 2021,（1）
• 所属期刊栏目: ARTICLES
• 页码范围: 35-42
• 页数: 8页
• 语种: 英文

摘要

A near-infrared non-fullerene acceptor (NFA) BDTIC, based on thienopyrrole-expanded benzo[1,2-b:4,5-b']dithiophene unit(heptacyclic 5,N-heteroacene) as core, is designed and synthesized. The aromatic pyrrole ring with strong electron-donating ability in the core enhances the intramolecular charge transfer effect, finely tunes the optical bandgap and absorption profile of BDTIC, and thus results in a narrowed optical bandgap (E°gpt) of 1.38 eV and a near-infrared absorption to 900 nm. When BDTIC is paired with donor polymer PBDB-T to fabricate organic solar cells, the optimized device achieves a best power conversion efficiency of 12.1％ with a short-circuit current density of 20.0 mA·cm-2 and an open-circuit voltage of 0.88 V. The photovoltaic performance benefits from the broad absorption, weak bimolecular recombination, efficient charge separation and collection, and favorable blend morphology. This work demonstrates that thienopyrrole-expanded benzo[1,2-b:4,5-b']dithiophene unit (heptacyclic S,N-heteroacene) is a promising building unit to construct high-performance NFAs by enhancing the intramolecular charge transfer effect, broadening absorption as well as maintaining good intermolecular stacking property.