Investigation of a novel inorganic cubic perovskite Ca3PI3 with unique strain‐driven optical, electronic, and mechanical properties

Abstract The remarkable structural, optical, and electronic characteristics of inorganic perovskite materials have generated significant enthusiasm within the field of solar technology. The material Ca 3 PI 3 belongs to the same category as inorganic metal halide perovskites. This research utilized the first‐principles density functional theory (FP‐DFT) to examine how the optical and electronic characteristics of Ca 3 PI 3 are impacted by strain. To accurately determine the band arrangement, we incorporated the relativistic spin‐orbit coupling (SOC) effect into our calculations. The planar Ca 3 PI 3 molecule has a direct bandgap of 1.582 eV (PBE) at its Г(gamma)‐point, but while the relativistic SOC effect is included, the bandgap decreases to 1.329 eV. Under compressive strain, the bandgap of all structures decreases, whereas under tensile strain, it increases. The optical characteristics of Ca 3 PI 3 , including the dielectric function, absorption coefficient, and electron loss function, indicate its strong absorption capabilities in the visible range, driven by its band properties. Besides, the photon energy spectrum displays a red‐shift (blue‐shift) in the absorption coefficient and dielectric function with increasing amounts of compressive (tensile) strain. Therefore, the study of the strain‐induced optical and electronic characteristics of Ca 3 PI 3 bears valuable implications for its potential use in the design of solar cells and optoelectronic devices.