Computational Investigation of KInCl3 Perovskite. A First Principle Approach

This paper presents a first-principles analysis of the structural, electrical, optical, and thermodynamic characteristics of cubic KInCl3 perovskite by density functional theory (DFT). The structural optimization verifies the mechanical stability of the system, indicating a marginally compressed lattice and a comparatively low bulk modulus of 22 GPa. The electronic band structure reveals a direction-dependent band gap, varying from a low 0.15 eV to a broad 5.40 eV gap, highlighting possibilities for ultraviolet (UV) optoelectronic applications. The density of states (DOS) study reveals substantial contributions from Cl-p and In-d orbitals in the valence band (VB), as well as from K-d and In-p orbitals in the conduction band (CB). The optical investigations of the structure demonstrate significant absorption in the ultraviolet spectrum, a static dielectric constant of 3.02, a maximum refractive index of 2.15, and a peak absorption coefficient of 1.17 × 108 m–1. The thermodynamic evaluations at different temperatures and pressures exhibit characteristic behavior in thermal expansion, entropy, heat capacity, and Debye temperature, thereby affirming thermal and mechanical stability. The results indicate that KInCl3 is a viable choice for high-energy optoelectronic, thermomechanical, and UV filtering applications.