A comprehensive DFT investigation of inorganic halide perovskites GaXCl3 (X = Ca, Sr, and Ba) for optoelectronics application

Abstract

In recent times, ABX3 halide perovskite materials have emerged as revolutionary components in photovoltaic solar cells, functioning as photoabsorbers. Recently, there has been significant research attention directed towards lead halide perovskites. Nevertheless, there is ongoing research to identify lead-free alternatives due to the toxicity of lead. Therefore, the present study utilizes density functional theory to investigate the physical characteristics of the lead-free halide perovskites GaXCl3 (where X represents Ca, Sr, and Ba). The study aims to assess the feasibility of GaXCl3 (X = Ca, Sr, and Ba) for use in optoelectronic applications through an analysis of its structural, electrical, optical, and mechanical properties. The band gaps of GaCaCl3, GaSrCl3, and GaBaCl3 compounds have been found to be 3.45 eV, 3.22 eV, and 2.92 eV, respectively, which correspond to higher indirect band gaps. Additionally, elastic constants were computed in order to gain insight into the mechanical characteristics of the substance. The results reveal that all three compounds exhibit positive elastic constant Cij values, demonstrating their mechanical stability. However, their phonon dispersion curves show some negative parts which indicate their dynamic instability with temperature. Considerable performance in optoelectronic technology can be deduced from the absorption and optical conductivity of ultraviolet and visible light.