Investigation of structural, electronic, optical, and photocatalytic properties of new double perovskites Cs

Inorganic halide perovskites, such as Cs₂InSbX₆ (X = F, Cl), have shown potential for next-generation solar cells and photocatalysis due to their light-capturing properties. However, concerns about stability and toxicity in lead-based perovskites drive the need for eco-friendly alternatives like antimony-based compounds. This study employed Density Functional Theory (DFT) calculations to explore how mechanical strain affects the electronic and optical properties of Cs₂InSbX₆. Without strain, Cs₂InSbF₆ and Cs₂InSbCl₆ exhibit bandgaps of 2.06 eV and 1.20 eV, respectively. We investigated how strain ranging from -5% to +5 % influences these materials' performance in optoelectronic and photocatalytic applications. Notably, negative strain enhances absorption and quantum efficiency for both compounds, particularly Cs₂InSbCl₆, which shows superior absorption in the visible spectrum. Our findings suggest that Cs₂InSbCl₆, with a tunable bandgap and favorable optical characteristics under strain, is a promising candidate for environmentally friendly applications, including solar cells and photocatalysis.