Solid‐State Dye‐Sensitized Solar Cells With Air‐Stable Cs ₂ SnI ₆ as Hole Transport Layer

Low‐cost, high‐performance dye‐sensitized solar cells (DSCs) are recognized as promising candidates for commercial applications. Electrolytes, a critical component of DSCs, are widely recognized as the main barrier to their long‐term stability. Solid‐state electrolytes, used as alternative materials in DSCs, address common issues with liquid electrolytes, such as leakage and volatilization. This study presents solid‐state DSCs that employ an air‐stable Cs 2 SnX 6 perovskite, free of additives, as the hole‐transporting material (HTM). The cells also use the organic dye MOTP‐Pyc as a sensitizer, which features a long‐lived charge separation state. The solar cells with Cs 2 SnX 6 HTM achieved a maximum power conversion efficiency (PCE) of 4.26% under AM 1.5 G illumination, with high reproducibility.