The Influence of PbI 2 on Characteristic of Organic-Inorganic Hybrid Perovskite Thin Films

Abstract

Organic-inorganic hybrid perovskite materials have attracted significant research efforts because of their outstanding properties. Meanwhile the crystallization of organic-inorganic hybrid perovskite materials can significantly influence the films quality. Here, we research the influence of the characteristics of PbI2 thin film on final perovskite films and the mechanisms of film formation based on the two-step sequential deposition method. We found that the characteristics of PbI2 thin film, such as the grain size, the grain shape, the surface roughness and the film densification, have significant effects on the final perovskite films due to different film crystallization process. According to the analysis on the characteristics of the perovskite films obtained from different PbI2 precursor, we suggested that the formation of perovskite film begins from the PbI2 crystals expanding when they are converted to MAPbI3 perovskite by migration of MA+ cations from the grain boundaries.