Pressure Tunable Properties of Calcium Arsenic Trihalide Perovskites from First Principles DFT

Metal halide perovskites have become pioneering compounds, significantly advancing solar energy, optoelectronics, and related fields. Although their structural, electronic, and mechanical behaviors have been widely investigated, the combined effects of halogen substitution and external pressure on the physical properties of Ca 3 AsX 3 ( X = F, Cl, Br, and I) remain unexplored. The study examined the physical properties of Ca 3 AsX 3 ( X = F, Cl, Br, and I) under halogen substitution and different hydrostatic pressures using first‐principles calculations based on density functional theory. These findings indicate that increasing pressure shortens interatomic distances, resulting in significant reductions in both lattice parameters and unit cell dimensions. Electronic analysis reveals that the substitution of the halide with increasing hydrostatic pressure leads to a tunable band gap. With elevated pressure, they attain mechanical stability and exhibit enhanced ductility and anisotropy. Their optical attributes improve under compression, with band gap narrowing contributing to better performance. These materials demonstrate strong light absorption, efficient electrical conductivity, minimal reflectance, and excellent dielectric behavior in the visible range, making them ideal for optical and energy storage applications. Additionally, their pronounced ultraviolet optical activity highlights their potential for ultraviolet radiation technologies. This research explains how pressure and halogen substitution affect the characteristics of halide perovskites, providing valuable insights for future innovations in optoelectronic applications.