MAPbCl3-Mediated Decomposition Process to Tune Cl/PbI2 Distribution in MAPbI3 Films

Abstract

Various methods have been developed to optimize the active layer of perovskite solar cells. To date, the introduction of excess PbI2 and chlorine doping are two typical means. Herein, an ion exchange–decomposition process was designed to combine these two approaches. In this process, the I–Cl exchange and MACl sublimation occurred simultaneously at elevated temperature, resulting in a PbI2-excess, Cl-doped perovskite film. This combined strategy could guarantee that as much chlorine as possible was doped into the perovskite crystal lattice, which enables the production of perovskite films with obviously reduced defect density and enhanced carrier diffusion length. Strikingly, the power conversion efficiency of the device is boosted from 17.17% to 20.15%.