Pressure-induced band gap engineering and enhanced optoelectronic properties of non-toxic Ca-based perovskite CsCaCl3: Insights from density functional theory

Abstract

This study investigates the impact of hydrostatic pressure on the structural, electronic, optical, and mechanical properties of the cubic halide perovskite CsCaCl3. The pressure effect reduces the interatomic distance, which has a significant impact on this perovskite's lattice constant and unit cell volume. The electronic band gap narrows under pressure from the ultraviolet to the visible range, making it simpler to transport electrons from the valence band to the conduction band and increasing the efficiency of optoelectronic devices. Additionally, at around 50 GPa pressure, the band gap nature changes from indirect to direct, making the material better suited for use in optoelectronic applications. A deep optical study has shown that CsCaCl3 might be used in surgical tools, integrated circuits, QLED, OLED, solar cells, waveguides, and solar heat reduction materials. The mechanical stability of CsCaCl3 under the full range of applied pressure is confirmed by the elastic constants, which perfectly follow the Born stability criteria, the CsCaCl3 phase is proven to be stable across the whole applied pressure range by the tolerance factor "t", and support the thermodynamic stability achieved by the negative values of formation enthalpy. External pressure has a major impact on the mechanical properties, making this compound more ductile.