Moisture-Stable Intermediate Phase Manipulation for Efficient Perovskite Solar Cells Fabricated in Ambient Air
Luyao Yan, Hao Huang, Peng Cui, Yingying Yang, Zhenhuang Su, Yi Lu, Min Wang, Zhineng Lan, Shujie Qu, Benyu Liu, Changxu Sun, Liang Li, Shuxian Du, Yang Fu, Xingyu Gao, Meicheng Li
Abstract
Fabricating high-efficiency perovskite solar cells (PSCs) in ambient air can facilitate their low-cost industrialization. However, the metastable wet-film stage before annealing during the film deposition process is susceptible to moisture invasion, making it difficult to form black-phase formamidinium lead iodide (α-FAPbI 3 ) perovskites in ambient air. Herein, we construct a moisture-stable intermediate phase dominated by δ-FAPbI 3 in the metastable wet-film stage using acetimidamidal acetate (AceAc). AceAc can induce the formation of δ-FAPbI 3 to resist the invasion of moisture on a wet film, further transforming the formed δ-FAPbI 3 into pure α-FAPbI 3 in the presence of MACl. The resulting PSCs fabricated in ambient air achieve a power conversion efficiency (PCE) of 26.5% (certified at 25.9%) and maintain 98% of the initial PCE after 11000 h of aging under air conditions (25% relative humidity (RH) and 25 °C).