Radical polymeric p-doping and grain modulation for stable, efficient perovskite solar modules
Shuai You, Haipeng Zeng, Yuhang Liu, Bing Han, Min Li, Lin Li, Xin Zheng, Rui Guo, Long Luo, Zhe Li, Chi Zhang, Ranran Liu, Yang Zhao, Shujing Zhang, Peng Qi, Ti Wang, Qi Chen, Felix T. Eickemeyer, Brian Carlsen, Shaik M. Zakeeruddin, Liqiang Mai, Yaoguang Rong, Michaël Grätzel, Xiong Li
Abstract
High-quality perovskite light harvesters and robust organic hole extraction layers are essential for achieving high-performing perovskite solar cells (PSCs). We introduce a phosphonic acid-functionalized fullerene derivative in mixed-cation perovskites as a grain boundary modulator to consolidate the crystal structure, which enhances the tolerance of the film against illumination, heat, and moisture. We also developed a redox-active radical polymer, poly(oxoammonium salt), that can effectively p-dope the hole-transporting material by hole injection and that also mitigates lithium ion diffusion. Power conversion efficiencies of 23.5% for 1-square-centimeter mixed-cation-anion PSCs and 21.4% for 17.1-square-centimeter minimodules were achieved. The PSCs retained 95.5% of their initial efficiencies after 3265 hours at maximum power point tracking under continuous 1-sun illumination at 70° ± 5°C.