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 CsPbI$_3$ 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 propertiesof 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.
Volume 43, 2020
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