Published on Journal of The American Chemical Society (10 February 2021)

Author(s): Huiting Fu, Yuxiang Li*, Jianwei Yu, Ziang Wu, Qunping Fan, Francis Lin, Han Young Woo, Feng Gao, Zonglong Zhu, and Alex K.-Y. Jen*

Abstract

Despite the significant progresses made in all-polymer solar cells (all-PSCs) recently, the relatively low short-circuit current density (J_sc) and large energy loss are still quite difficult to overcome for further development. To address these challenges, we developed a new class of narrow-bandgap polymer acceptors incorporating a benzotriazole (BTz)-core fused-ring segment, named the PZT series. Compared to the commonly used benzothiadiazole (BT)-containing polymer PYT, the less electron-deficient BTz renders PZT derivatives with significantly red-shifted optical absorption and up-shifted energy levels, leading to simultaneously improved J_sc and open-circuit voltage in the resultant all-PSCs. More importantly, a regioregular PZT (PZT-γ) has been developed to achieve higher regiospecificity for avoiding the formation of isomers during polymerization. Benefiting from the more extended absorption, better backbone ordering, and more optimal blend morphology with donor component, PZT-γ-based all-PSCs exhibit a record-high power conversion efficiency of 15.8% with a greatly enhanced J_sc of 24.7 mA/cm2 and a low energy loss of 0.51 eV.

Read more: https://doi.org/10.1021/jacs.0c12527