Investigation of Excitons Properties in Atomically Thin CsPbBr3 Perovskite Film

CsPbX3 inorganic perovskites have gained widespread attention due to the excellent stability and interesting properties. This article focuses on the exciton properties of CsPbBr3 with different layer numbers. The electronic and optical properties are also investigated. The distribution of excitons (electrons and holes) is closely related to the density of states near the bottom of the conduction band and the top of valence band. Based on potential analysis, it is found that the excitons are affected by the bromine atoms. With increasing thickness, the bandgap decreases and the absorption spectrum that appears obviously in the bandgap moves to lower energy, the maximum binding energy of bright excitons becomes smaller, and the corresponding Bohr radius becomes larger. These results provide a theoretical basis for the theoretical and experimental studies of CsPbBr3 and provide some guidance for the design of optoelectronic devices.