Hybrid Lead Halide Perovskite Films with Large Grain Size Via Spin-Coating Free Fabrication

Herein, a spin-coating-free method to deposit CH3NH3PbI3 perovskite films with large grains is demonstrated. The effect of processing temperature on the property of hybrid lead halide perovskite films is investigated. It is found that the grain domain size is enlarged by increasing processing temperature. Dense and uniform CH3NH3PbI3 films with grain domain size close to 1mm are obtained using this method. A higher processing temperature also promotes the conversion from precursors solution to perovskite, but excessive temperature induces a poor crystalline state. About 150 degrees C is proved to be close to the optimal processing temperature to form perovskite films with less defect density, lower charge recombination, and longer charge carrier lifetimes. Space-charge-limited current method is used to investigate the charge transport efficiency based on CH3NH3PbI3 perovskite films. The results show that both the electron and hole mobility improve remarkably as the processing temperature increases.