Highly efficient and stable inorganic CsPbBr3 perovskite solar cells via vacuum co-evaporation

High power conversion efficiency (PCE) and good long-term stability are everlasting pursuit for perovskite solar cells. We present here CsPbBr 3 perovskite film deposited by vacuum co-evaporation of CsBr and PbBr 2 . By optimizing evaporation rate ratio of the two precursor and annealing temperature, perovskite films with large grain and high crystallinity are obtained. Furthermore, by regulating spinning speed of TiO 2 precursor solution and thickness of CsPbBr 3 film, a best PCE of 9.43% is recorded under 100 mW cm −2 illumination, providing a significant enhancement in contrast with 6.26% of device based on spin-coating method. Additionally, the PCE of resulting perovskite solar cell without encapsulation remains at 96% of initial value after storing for 480 h under humidity of 40% in air. Our findings in this work deliver an effective strategy to fabricate high-performance inorganic perovskite solar cells.