Preparation of CH3NH3PbI3 thin films for solar cells via Vapor Transfer Method

Organometal halide perovskite based solar cells have emerged as one of the most promising candidates for low-cost and high-efficiency solar cell technologies. Here a Vapor Transfer Method (VTM) is used to fabricate high quality perovskite thin films in a balanced vacuum capsule. By adjusting the reaction temperature, CH3NH3I saturated vapor which then reacts with PbI2 films can be controlled and the formation process of CH3NH3PbI3 perovskite films can be further influenced. Prepared perovskite films which exhibit pure phase, smooth surface and high crystallinity are assembled into planar heterojunction inverted solar cells. The whole fabrication process of solar cell devices is organic solution free. Finally, the champion cell achieved power conversion efficiency (PCE) of 13.08% with negligible current-voltage hysteresis under fully open-air conditions. The photovoltaic performance could be further enhanced by optimizing perovskite composition and the device structure. (C) 2018 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.