Efficient Inorganic Cesium Lead Mixed-Halide Perovskite Solar Cells Prepared by Flash-Evaporation Printing

Cesium-based inorganic perovskites have attracted enormous interest for efficient and stable photovoltaics, while still a few studies apply evaporation methods with high reproducibility to prepare them. Herein, high-quality CsPbI2Br films are deposited by flash-evaporation printing (FEP), a single source evaporation method using laser as the heating source and carbon nanotube sheets as the evaporator. Uniform films with balanced stoichiometry and high crystallinity can be obtained by controlling the precursor ratio and post-annealing conditions. Planar solar cells using these inorganic perovskite films exhibit champion power conversion efficiencies of 12.2% in small areas (0.06 cm(2)) and 9.4% in large areas (1 cm(2)) with insignificant hysteresis, indicating that the FEP method is a promising way in preparing high-quality inorganic perovskite films for efficient large-area devices.