A comparative study of structural, electronic and optical properties of cubic CsPbI_3: bulk and surface

摘要

In order to acquire a reasonable description of the structural, electronic and optical properties of the perovskite compound CsPbI_3, first principle calculations have been computed by density functional theory implemented in the WIEN2k code. The calculations are presented within PBE-sol for exchange correlation functions coupled with modified-Becke-Johnson (mBJ) exchange potential. The (001) surfaces of CSPbI_3 for varying thicknesses have been constructed using the Structeditor program implemented in the WIEN2k code. The lattice constant, band gap and DOS have been computed. The CsPbl3 bulk and surface exhibit a direct band gap located at the R symmetry point of the Brillouin zone. The band gap approaches experimental values when the exchange correlation function is coupled with mBJ. The optical properties of CsPbI_3 were computed in terms of dielectric properties, refractive index, extinction coefficient, absorption coefficient, conductivity, reflectivity and energy loss. The direct band gap nature and high-absorption power of the surfaces of CSPbI_3 in the (001) direction in the infrared, visible and ultraviolet energy range make it suitable for use in optical and optoelectronic devices.