Fabrication of single phase CsPbBr3 films via in situ metal reaction

Abstract

Inorganic perovskite CsPbBr₃ is a suitable candidate owing to its excellent stability and outstanding visible light absorption. However, it is a huge challenge to fabricate single phase CsPbBr₃ films. Herein, we developed an in situ metal reaction strategy to fabricate single phase CsPbBr₃ films by reacting Pb precursors with CsBr/HBr in methanol solution. The thickness of the sputtered Pb film plays a key role in inhibiting the formation of a secondary CsPb₂Br₅ phase. The results indicate that the single phase CsPbBr₃ films can be obtained by using below 40 nm of the sputtered Pb films, and the single phase CsPbBr₃ device architecture exhibits 4.08% power conversion efficiency. This device can retain over 95% of the initial efficiency after 30 days of storage without packaging in an ambient environment.