Efficient Perovskite Solar Cells Made by Using a Vapor‐Assisted Hot Crystallization Method in Air

Abstract Perovskite solar cells (PSCs) achieve remarkable progress in recent years. However, their commercialization remains hindered by conventional fabrication processes that require antisolvent and prolonged annealing, which compromises scalability and cost‐effectiveness. In this study, a vapor‐assisted hot crystallization method is proposed, in which a vapor atmosphere is applied during the crystallization process to improve quality of perovskite films. The crystallization and annealing process takes less than 3 min, which is much faster than the antisolvent spin‐coating method. In addition, the method can be performed in ambient air without using antisolvent. Systematic characterization demonstrates that solvent vapor atmospheres enhance crystallinity, suppress defect formation, and promote denser growth at grain boundaries. Through synergistic modulation of vapor compositions, large‐domain, uniform, and pinhole‐free perovskite films are obtained. A power conversion efficiency (PCE) of 23.72% is achieved, which is the highest PCE for perovskite solar cells made by using hot‐crystallization method.