Investigation of structure, optoelectronic, and thermodynamic properties of gallium-based perovskites GaMF3 (M = Ca, and Cd) for solar cell applications

Using the full potential density functional theory (DFT), structural, electronic and optical properties as well as thermodynamic attributes of GaMF3 (M = Ca and Cd) were studied. In this investigation, electronic and optical characteristics were assessed using the (GGA + U) functional whereas the thermodynamic characteristics of the perovskite were assessed using the Gibbs code. The negative formation energy confirms structural stability. Whereas GaCaF3 shows a direct band gap, while GaCdF3 exhibits indirect energy band gap. Density of states plots indicated the presence of mixed ionic and covalent connections. Optical characteristics are predicted in the energy span of 0-12 eV, including reflectivity, refractive index, absorption coefficients, real and imaginary parts of dielectric functions, and optical conductivity. These materials have a small reflectivity and high absorption in the Ultraviolet region, which makes them good candidates for optoelectronic materials. The negative Gibbs free energy indicate that these materials are stable and can be synthesize at room temperature. This work sheds light on the behavior and composition of perovskites for optoelectronic application.