Abstract
•Double perovskites halides K2AgBiX6 (X = Cl, Br) are executed in terms of density functional theory.•Structural and thermodynamic investigation depict structural stability of K2AgBiX6 in cubic phase.•The electronic band structures and optical analysis show both halides are strong candidate for the fabrication of solar cell devices.•Calculated thermoelectric parameters indicate that the both halides can be used even at elevated temperatures.
Lead-free double-perovskites (DPs) K2AgBiX6 (X = Cl, Br) has been executed as well as examined by ab-initio computations for solar cell energy sources. Improved and latest Becke and Johnson potential (TB-mBJ) has been suggested to calculate optoelectronics characteristics. The lattice constants reported theoretical and computed values using Perdew-Burke-Ernzerhof's generalized-gradient-approximation (PBEsol-GGA) had been determined in good agreement. The calculated bandgap 2.3 eV (K2AgBiCl6) and 1.5 eV (K2AgBiBr6) disclosed their indirect nature, which showed that these are suitable potential candidates for visible light solar-cell (SC). Optical ranges explain the dielectric-constant, light absorption and reflection, and refractive index. The maximum absorption band has been noted within the wavelength of 620–310 nm. In addition, the BoltzTraP (BT) Code has been determined thermoelectric characteristics that result in higher value Seebeck coefficient and lower thermal conductivity. Hence, executed theoretical calculation proposed that examined material has potential application in renewable energy fields.