A comparative study of the structural, electronic, and optical properties of Ca₃SbCl₃ halide perovskite using DFT-GGA and HSE06 functional for photovoltaic applications

This study presents a detailed analysis of Ca₃SbCl₃ halide perovskite revealing its potential for photovoltaic applications. We studied structural, electronic, and optical properties of Ca₃SbCl₃ halide perovskite using Density Functional Theory (DFT) with GGA and HSE06 hybrid functionals. We found that the material exhibits a cubic crystal structure with a lattice constant of 6.00 Å, a density of 2.678 g/cm³. This material belongs to the Pm-3 m (221) space group, indicating a highly symmetric and stable arrangement. Ca₃SbCl₃ shows a direct band gap of 1.814 eV using GGA, while the HSE06 method indicates 2.67 eV, ideal for photovoltaic and optoelectronics applications. We identified significant absorption peaks at 3.32 eV (1.26 × 10⁵ cm⁻¹) and 3.76 eV (2.82 × 10⁵ cm⁻¹). We also reported the refractive indices as 2.01 (GGA) and 1.76 (HSE06), which are in excellent agreement with the benchmark values typically ranging from 1.0 to 2.0 for efficient solar cells. Additionally, the study highlights the crucial roles of Ca, Sb, and Cl atoms in the electronic structure, with pronounced charge localization around Ca and Sb atoms. Our study is a testimony that Ca₃SbCl₃ has a strong light absorption and favourable optical properties, suggesting it as a promising candidate for solar energy harvesting.