A Low‐Temperature Additive‐Involved Leaching Method for Highly Efficient Inorganic Perovskite Solar Cells

Abstract

Abstract Inorganic CsPbI 3 perovskite with an optical bandgap ranging from 1.67 to 1.75 eV is a promising light‐harvesting material as a top cell in tandem solar cells, but its high fabrication temperature can damage the middle layers or the bottom subcells. Here, an additive‐involved leaching method to fabricate CsPbI 3 perovskite films is demonstrated, which can decrease the preparation temperature to 100 °C. The CsPbI 3 perovskite films with high crystallinity are achieved by a solution assisted reaction between DMAPbI 3 and Cs 4 PbI 6 with the leaching of DMA + , Cs + , and I − . The as‐prepared CsPbI 3 perovskite films exhibit much superior stability compared to their high‐temperature counterparts. As a result, a power conversion efficiency of over 16% is obtained, and the unencapsulated device maintains over 93% of the initial efficiency after aging for 30 days in air with a relative humidity of 10%.