Tuning of band gap by variation of halide ions in K₂CuSbX₆ (X = Cl, Br, I) for solar cells and thermoelectric applications

The double perovskites have obtained remarkable attention in the field of solar cells and renewable energy applications. Here in present article, the optical and transport properties of K₂CuSbX₆ (X = Cl, Br, I) are illustrated by DFT based simulation WIEN2K codes. The formation energy has been calculated for thermodynamic stability. The indirect band gaps (1.12, 0.80, and 0.43) for (Cl, Br, I) studied DPs halides are reported from band structures which instigate diverse optoelectronic and transport applications. The width of absorption band increases from Cl to I and shifted towards to lower frequency region. Furthermore, thermoelectric parameters are evaluated in the temperature range 200–600K and chemical potential ±0.15 eV. The ultralow values of lattice conductivity and large ZT at 300K increases their significant importance for thermoelectric generators and renewable energy devices.