Bandgap-tunable double-perovskite thin films by solution processing

Narrowing the bandgap of lead-free double-perovskite Cs2AgBiBr6 is required for using this material in future photovoltaics. Herein, we demonstrate a bandgap engineering of Cs2AgBiBr6 by introducing Sb to substitute up to 75% of Bi via a versatile solution-processed method in dimethyl sulfoxide at 180 °C. The resultant Cs2AgSbxBi1−xBr6 (x = 0, 0.25, 0.50, 0.75) thin films possess high crystallinity and good thermostability. Moreover, the Sb...