Key Strategies for the Performance Enhancement of Tin-Based Perovskite Solar Cells

Tin-based perovskite solar cells (TPSCs) have emerged as one of the most promising alternatives to lead-based perovskite solar cells owing to their favorable electronic structure, low cost, and environmental compatibility, satisfying the key requirements of a high-performance thin-film solar cell. However, the weaker relativistic stabilization of the 5s2 electron pair in Sn makes the +2 oxidation state intrinsically less stable, rendering Sn2+ highly susceptible to oxidation into Sn4+. Meanwhile, achieving high-quality tin perovskite films with controlled crystallization is considerably more challenging than its lead-based counterparts. In recent years, tremendous efforts have been devoted to suppressing tin oxidation, improving film quality, and optimizing device architectures, collectively leading to rapid efficiency gains in TPSCs. This Perspective summarizes the recent important progress in TPSCs, encompassing both pure tin and tin–lead mixed perovskite solar cells, and discusses the key strategies for further enhancing device performance.