Investigation of electronic, optical and thermoelectric features of X2ScAgCl6 (X=K, Na) double perovskites for renewable energy applications

In the frame of density functional theory (DFT), structural, thermoelectric, electronic, and optical features of cubic X2ScAgCl6 (X = K, Na) double perovskite are studied. The outcomes of formation energy (delta H) and tolerance factor (tau) confirm the stability of X2ScAgCl6 (X = K, Na) compounds in the cubic phase. K2ScAgCl6 and Na2ScAgCl6 have direct bandgap (E-g) values of 3.65 eV and 3.63 eV, respectively. Optical characteristics such as refractive index n (omega), optical conductivity sigma ( omega), reflectivity R (omega), extinction coefficient k (omega), absorption coefficient alpha(omega), and dielectric constants (epsilon(1), epsilon(2)) are also calculated. Moreover, the thermoelectric features are computed by using BoltzTrap Code. The computed value of figure of merit (ZT) for K2ScAgCl6 and Na2ScAgCl6 is 0.782 and 0.798, respectively shows both compounds are suitable for thermoelectric applications. The analysis of structural and optoelectronic features reveals that the X2ScAgCl6 (A = K, Na) compounds has appropriate photo absorbers tendency for solar cells and ultraviolet (UV) photodetectors.