Compositional Design for High-Efficiency All-Inorganic Tin Halide Perovskite Solar Cells

Metal halide perovskite solar cells have advanced rapidly with exceptional power conversion efficiencies (PCEs). However, the toxicity of lead-based perovskites necessitates a transition toward non-toxic alternatives. This study explored the potential of inorganic tin-based halide perovskites, such as CsSnX3, as viable alternatives. Despite their inherent advantages, these perovskites face efficiency challenges, owing to significant open-circuit voltage deficits, stability issues, and oxidation issues. We addressed these challenges through the compositional engineering of CsSn(I1–xBrx)3 perovskites, utilizing ab initio thermodynamic calculations to determine the optimal compositions. Our approach was validated by fabricating CsSn(I1–xBrx)3 perovskite solar cells with varying Br contents, guided by our theoretical framework. Notably, our highest efficiency reached 11.87% with the CsSnI2Br composition, marking the highest PCE for inorganic tin perovskite solar cells to date, which was accomplished without special additives. This study provides a potential pathway for further enhancing the stability and efficiency of tin-based perovskite solar cells.