Nonfused Nonfullerene Acceptors with an A-D-A′-D-A Framework and a Benzothiadiazole Core for High-Performance Organic Solar Cells

作者：Pang, Shuting; Zhou, Xia; Zhang, Song; Tang, Haoran; Dhakal, Sujata; Gu, Xiaodan; Duan, Chunhui^*; Huang, Fei^*; Cao, Yong

来源：ACS applied materials & interfaces, 2020, 12(14): 16531-16540.

DOI：10.1021/acsami.0c01850

• organic solar cells
• nonfullerene acceptors
• nonfused acceptors
• A-D-A '-D-A framework
• benzothiadiazole

Nonfullerene acceptors (NFAs) have contributed significantly to the progress of organic solar cells (OSCs). However, most NFAs feature a large fused-ring backbone, which usually requires a tedious multiple-step synthesis, and are not applicable to commercial applications. An alternative strategy is to develop nonfused NFAs, which possess synthetic simplicity and facile tunability in optoelectronic properties and solid-state microstructures. In this work, we report two nonfused NFAs, BTCIC and BTCIC-4Cl, based on an A-D-A'-D-A architecture, which possess the same electron-deficient benzothiadiazole central core but different electron-withdrawing terminal groups. The optical properties, energy levels, and molecular crystallinities were finely tuned by changing the terminal groups. Moreover, a decent power conversion efficiency of 9.3 and 10.5% has been achieved by BTCIC and BTCIC-4Cl, respectively, by blending them with an appropriate polymer donor. These results demonstrate the potential of A-D-A'-D-A type nonfused NFAs for high-performance OSCs. Further development of nonfused NFAs will be very fruitful by employing appropriate building blocks and via side-chain optimizations.