Abstract
The optical and transport properties of ZYbI(3) (Z = Rb, CS) are studied systematically by WIEN2k code. The tolerance factor scrutinized the structural stability while formation energy thermodynamic stability. The band structures show that RbYbI3 and CsYbI3 have direct bandgap values 1.22 eV and 1.12 eV, respectively, which are considered finest for solar cells. The optical characteristics of the studied materials are elaborated by dielectric constants and their dependent parameters. The maximum absorption of light has been noted in the visible energy region. The transport properties are calculated by BoltzTraP code. The figure of merit (0.82 at 300K) for these materials is remarkable which increase their importance. Therefore, studied materials are suitable for clean energy in optoelectronic, and thermoelectric devices.