Fabrication and Growth Mechanism of Uniform Suspended Perovskite Thin Films

Crystallization and morphology control are fundamental challenges in the preparation of perovskite thin films. In this article, we demonstrate the fabrication of large area and uniform CH3NH3PbBr3 suspended films on a periodic microstructure. Compared with the conventional perovskite film, the suspended perovskite film proves to have a better optical performance from both aspects of the simulation and the characterization. Studies on the growth mechanism reveal that both the capillary-induced adhesion and the solvent evaporation rate play important roles in controlling the morphology and formation of the suspended film. In particular, the capillary-induced adhesion supports the precursor-solution film on the nanobowl-like structures, while the dynamic-dripping (DD) method is utilized to accelerate the solvent evaporation rate and promotes the formation of the transition-state film. In situ photoluminescence characterization is employed to investigate the growth kinetics of the crystals in the transition-s...