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.