FIRST-PRINCIPLES CALCULATIONS TO INVESTIGATE THE STRUCTURAL, ELASTIC, MECHANICAL AND ELECTRONIC PROPERTIES OF INORGANIC HALIDE PEROVSKITE Ba3AsCl3 FOR OPTOELECTRONICS AND SOLAR CELL APPLICATIONS

Abstract

Inorganic halide perovskites have drawn a lot of attention in recent years because of their exciting potential in areas like solar energy, optoelectronics, and photocatalysis. This study presents a detailed first-principles calculations of the structural, elastic, mechanical, and electronic properties of bulk Ba₃AsCl₃ perovskite using Density Functional Theory (DFT) as implemented in Quantum Espresso code and Thermo-PW. The generalized gradient approximation (GGA) with Perdew–Burke–Ernzerhof (PBE) functional was utilized to determine the electron exchange and correlation energy and a plane-wave energy cutoff of 70 eV and Monkhorst-Pack k-point grid of 10×10×10 were utilized to maximize the precision of characteristics calculations. Geometry optimization and variable-cell relaxation confirms the stability of the compound in its cubic phase with optimized lattice parameter of 6.49 which is in good agreement with available theoretical data. The calculated elastic constants satisfy the Born mechanical stability criteria.  The Bulk modulus, Young modulus, Shear modulus and Poisson's ratio were calculated from the obtained elastic constants and reveals that Ba₃AsCl₃ is mechanically stable with slightly brittle behavior.  Kleimann parameter, machinability index and anisotropy index were also investigated. Electronic band structure shows that Ba₃AsCl₃ is a direct band gap semiconductor, with a band gap of 0.976. The density of states (DOS) and PDOS shows the valence band maximum and conduction band minimum located along high symmetry points and the contributions of the orbitals in the electronic state. These findings provide key insights into the properties of Ba₃AsCl₃ and suggest its potentials in optoelectronics and solar cell applications.