Decoupling light- and oxygen-induced degradation mechanisms of Sn–Pb perovskites in all perovskite tandem solar cells

This study showed PEHCl-CN can enhance the strength of Sn–I, resulting in good light stability. The subsequent doping of MBI resulted in good air stability. This enables the integrated 2T all-perovskite device to achieve an efficiency of 27.9%.