Stable and uniform self-assembled organic diradical molecules for perovskite photovoltaics
Wenping Wu, Han Gao, Lingbo Jia, Yuan Li, Dezhong Zhang, Hongmei Zhan, Jianan Xu, Binhe Li, Ziran Geng, Yanxiang Cheng, Hui Tong, Yanxiong Pan, Jun Liu, Y.H. He, Xixiang Xu, Zhenguo Li, Bo He, Min Zhou, Lixiang Wang, Chuanjiang Qin
Abstract
Organic self-assembled molecules (SAMs), which are widely used in perovskite solar cells (PSCs), should exhibit enhanced performance to support the ongoing advancement of perovskite photovoltaics. We designed diradical SAMs through a coplanar conjugation of a donor-acceptor strategy to facilitate hole transport across the SAMs. The diradical SAMs exhibited high photothermal and electrochemical stability as well as improved assembly uniformity and large-area solution processability attributed to molecular steric hindrance design. We used an advanced scanning electrochemical cell microscopy–thin-layer cyclic voltammetry technique to accurately determine the carrier transfer rate, stability, and assembly properties of the SAMs. Ultimately, the efficiencies of the PSCs exceeded 26.3%, minimodules (10.05 cm 2 ) reached 23.6%, and perovskite-silicon tandem devices (1 cm 2 ) surpassed 34.2%. The PSCs maintained >97% after 2000 hours tracking at 45°C.