First-principles DFT investigation of strain and spin-orbit coupling effects on the optical and electrical properties of Ca₃SbI₃ inorganic halide perovskite-like for solar cell and optoelectronic applications

In the last few years, inorganic perovskite materials have attracted much attention in solar cell technology due to their excellent structural, optical and electrical properties. The scope of this paper is the cubic metal halide perovskite Ca 3 SbI 3 with space group Pm-3m (No. 221). In this paper, we investigate the effect of strain and spin-orbit coupling (SOC) on the optical and electronic properties of Ca 3 SbI 3 using first-principles density functional theory (DFT) within the generalized gradient approximation (GGA-PBE). The direct bandgap for unstrained Ca 3 SbI 3 is calculated to be 1.484[Formula: see text]eV, which gets redshifted to a value of 1.302[Formula: see text]eV once the SOC is included. However, this perovskite band gap may be modulated by applying biaxial strain. With compressive strain, its value decreases, whereas with tensile strain, it shows a small increase. The result from the analysis of the dielectric constant represents an excellent light visible absorption that, with applied compressive or tensile stress, shifts their peaks to a lower or higher energy of a photon, correspondingly. These results highlight the potential of Ca 3 SbI 3 in solar cells and optoelectronic devices, pointing out the relevance of strain engineering in setting its electronic and optical properties.