First principle study of lead‐free double perovskites halides<scp>Rb<sub>2</sub>Pd</scp>(Cl/Br)<sub>6</sub>for solar cells and renewable energy devices: A quantum<scp>DFT</scp>
Q. Mahmood, Muhammad Younas, Muhammad Gul Bahar Ashiq, Shahid M. Ramay, Asif Mahmood, Hamid M. Ghaithan
Abstract
Lead-free double perovskites are promising materials for environmental friendly photovoltaics and other optoelectronics. In this article, optical, thermoelectric, and thermodynamic properties of Rb2Pd(Cl/Br)6 are explored by modified Becke and Johnson potential. The Goldschmidt tolerance factor (0.90-1.04) ensures the cubic phase is structurally stable. The negative formation energy and positive phonon dispersion authenticate the thermodynamic stability. The band gap of Rb2PdCl6 is 1.88 eV, which reduces to 1.21 eV by replacing Cl with Br anion. The first absorption regions (620-413)nm for Rb2PdCl6 and (826-496)nm for Rb2PdBr6 increase their solar cells' implication. The transport properties are investigated by Boltzmann transport theory through the BoltzTraP code. Finally, the high values 0.76 and 0.75 of the figure of merit at room temperature also ensure their importance for thermoelectric generators.