Lead halide–templated crystallization of methylamine-free perovskite for efficient photovoltaic modules
Tongle Bu, Jing Li, Hengyi Li, Congcong Tian, Jie Su, Guoqing Tong, Luis K. Ono, Chao Wang, Zhipeng Lin, Nianyao Chai, Xiaoli Zhang, Jingjing Chang, Jianfeng Lu, Jie Zhong, Wenchao Huang, Yabing Qi, Yi‐Bing Cheng, Fuzhi Huang
Abstract
Suppressing nucleation over large areas Although formamidinium-based lead iodide (PbI 2 ) perovskites have a favorable bandgap and good thermal stability, the difficulty in controlling nucleation makes it difficult to grow high-quality, large-area films compared with methylammonium counterparts. Bu et al. show that adding N -methyl-2-pyrrolidone to the perovskite precursors forms an adduct with PbI 2 that promotes the formation of the desired black α-phase at room temperature. The addition of potassium hexafluorophosphate eliminated hysteresis by passivating interfacial defects and promoted long-term thermal stability at 85°C in unencapsulated devices. Large-area modules (17 square centimeters) achieved power conversion efficiencies of 20.4%. Science , abh1035, this issue p. 1327