摘要
The difficulties and solutions of vacuum processing for perovskite device fabrication were reported. By separating two perovskite precursors in two distinct chambers and monitoring and controlling the gas-vapor-like organic halides with a full-range vacuum pressure gauge and vacuum gate valve, smooth, yet highly crystalline perovskite thin films with micrometer-sized crystal domains can be obtained. These perovskite films were integrated with newly designed vacuum sublimed tri-layer hole transporting and bi-layer electron transporting structures. Highly efficient all-vacuum processed perovskite solar cells with the best PCE up to 17.6% are demonstrated. The absence of the characteristic absorption features and the diffraction peaks of metal halide in the medium and higher organic halide pressure samples indicates a total conversion of metal halide to perovskite upon organic halide sublimation. The results indicate that under too low organic halide vapor pressure the metal halides could not fully convert to perovskite.