Durable All Inorganic Perovskite Tandem Photovoltaics

Inorganic perovskite tandem solar cells (IPTSCs) are promising candidates to break the efficiency bottleneck and address the stability issue. However, challenges remain in fabricating 2-terminal (2T) IPTSCs due to the inferior film formation and deep trap states induced by tin cations. Herein, a green ligand evolution (GLE) strategy with p-toluenesulfonyl hydrazide is employed to regulate film formation and eliminate deep traps in inorganic narrow bandgap perovskite, enabling the successful development of 2T IPTSCs. Accordingly, the 1.31 eV CsPb0.4Sn0.6I3:GLE device delivers a record efficiency of 17.41%. Combined with the 1.92 eV CsPbI2Br top-cell, 2T-IPTSCs exhibit a champion efficiency of 22.57% (certified 21.92%). Additionally, IPTSCs are engineered to deliver remarkable operation durability under maximum power point tracking, maintaining 80% of the initial efficiency at 65 ℃ for 1510 h and 85℃ for 800 h, respectively.