Computational Exploration of Innovative Lead‐Free DPs X₂CdZnCl₆ (X = Na and K) DFT Analysis of Optoelectronic, Mechanical and Thermoelectric Performance

Abstract Based on DFT computation, the physical properties of newlead‐free double perovskites (DPs) X 2 CdZnCl 6 (X = Na and K) is carried out within WIEN2K software. The measured formation energy (ΔE f ) and tolerance factor indicate the cubic structure stabilities of investigated materials. The lattice parameters of the compounds Na 2 CdZnCl 6 and K 2 CdZnCl 6 are equal to 9.98 A° and 10.05 A°, respectively. The examination of the electronic structure through nKTB‐mBJ demonstrates that lead free DPs X 2 CdZnCl 6 (X = Na and K) exhibit semiconducting behavior with direct bandgap energy. The analysis of optical parameters reveal that the examined compounds have a stronger absorption property in UV region and make them well suited for photovoltaic devices and next‐generation technologies. Additionally, using BoltzTrap code, the thermoelectric characteristics are thoroughly examined. The highest Seebeck coefficient values 218.32 and 254.29 µV K −1 for X = Na and K, respectively. According to calculations, the maximum ZT values of 0.7 for Na 2 CdZnCl 6 and 0.73 for K 2 CdZnCl 6 indicate their potential as promising materials for thermoelectric devices. The acquired figure of merit (ZT) values indictes that examined lead free DPs X 2 CdZnCl 6 (X = Na and K) exhibit potential for implementation in thermoelectric devices.