The Electronic, Optical, and Thermoelectric Nature of Cs ₂ InAgX ₆ (X = Cl, F) Halide Perovskites: For Advanced Optoelectronic Applications

Halide-based double perovskites are appealing choices for optoelectronic devices due to their adjustable energy gaps and enhanced structural stability compared to conventional perovskites. They are also strong candidates for efficient energy conversion systems due to their remarkable thermoelectric properties. In the present study, we used first-principles calculations and extensively examined the structural, electronic, optical, and transport features of cubic-phase Cs₂InAgX₆ (X = Cl, F) double perovskites. The TB-mBJ potential revealed semiconducting nature with direct band gaps of 2.53 eV for Cs₂InAgCl₆ and 4.39 eV for Cs₂InAgF₆, respectively. Additionally, the optical response is studied to evaluate its possibilities in devices used in optoelectronics. Significant absorption exists in the ultraviolet range with the vital absorption peaks noticed between 8.0 and 13.0 eV. At 50 K, the ZT values were reported to be 0.99 for both materials. This study reveals that these materials are excellent choices for next-generation functional devices because of their remarkable optoelectronic and thermoelectric qualities.