Cs₂InGaX₆ (X=Cl, Br, or I): Emergent Inorganic Halide Double Perovskites with enhanced optoelectronic characteristics

During the last decade, Inorganic Halide Double Perovskite materials have attracted widespread interest as a promising eco-friendly and non-toxic alternative to lead based hybrid halide organic–inorganic perovskites materials, with outstanding Stability, Structural and electronic properties. In this study, First-Principles density functional theory (DFT) calculations were performed on the structural, stability, electronic and optical properties of the transition metal-based double perovskites materials Cs₂InGaX₆ (X = Cl, Br, or I). Our results reveal that all these materials exhibit excellent thermodynamic and structural stability owing to their negative formation energies and Goldsmith's factors. It is also observed that Cs₂InGaCl₆, Cs₂InGaBr₆, and Cs₂InGaI₆ materials exhibit band gaps calculated by different functional (GGA-PBE and TB-mpj) in visible-range between 0.89 and 3.24 eV. Furthermore, the computed optical properties reveal strong absorption in UV, visible, and IR range with high optical conductivity and low reflectivity. These obtained results predict that the three transition metal-based double perovskites materials carries promising application in nano-electronic and optoelectronic device applications and can be considered as photovoltaic absorber materials.