The study of new double perovskites K₂AgAsX₆ (X = Cl, Br) for energy-based applications

Halide double perovskites are the best alternative to Pb-halide perovskites. These materials play an important role in renewable energy generation. Therefore, we explore the physical properties of K₂AgAsX₆ (X = Cl, Br) double halide perovskites using full potential linearized augmented plane wave method. The structural parameters are calculated by optimization and analytical schemes. The negative values of formation energy confirm the thermodynamic stability, while Goldsmith’s tolerance factor guarantees the structural stability of both the double perovskites. The bandgaps of K₂AgAsCl₆ and K₂AgAsBr₆ are calculated as 2.10 and 1.48 eV, respectively by modified Becke and Johnson potential. Optical properties are examined in terms of the dielectric function, refractive index and absorption coefficients. The thermoelectric properties are calculated in terms of the electronic and thermal conductivities, Seebeck coefficients, power factor and figure of merit. Our study suggests the K₂AgAsX₆ perovskites for energy-related applications.