All-inorganic CsPb1-xSnxI2Br perovskites mediated by dicyandiamide additive for efficient 4-terminal tandem solar cell

Dicyandiamide (DCD) is used to regulate the crystallization and passivation of all-inorganic CsPb1-xSnxI2Br films, thus the power conversion efficiency (PCE) of the inverted CsPb0.6Sn0.4I2Br:DCD perovskite solar cell (PSC) increases to 14.17%. Meanwhile, the target all-inorganic perovskite 4-terminal (4T) tandem solar cell consisting of a semitransparent CsPbI2Br:DCD top PSC and a CsPb0.6Sn0.4I2Br:DCD bottom PSC achieves an efficiency of 19.61%.