First Principles Calculations of Structural, Phonon, Mechanical, Optoelectronic, Photovoltaic, Thermoelectric and Thermodynamic Properties of Inorganic Novel Cubic Halide Perovskites Ca3AsX3 (X = Br, I) a DFT Study

Lead-free halide perovskites have garnered a lot of interest in researchers because of their pertinent properties. This paper examined the structural, phonon, mechanical, electronic, optical, photovoltaic, thermoelectric, and thermodynamic properties of Ca₃AsX₃(X = Br, I) using density functional theory calculations executed in the WIEN2k program. All of the compounds have been shown to be thermodynamically and dynamically stable after extensive investigation into their phase stability. The thermodynamic stability is checked using formation energy, and the dynamical stability is checked using phonon dispersion. These compounds' structural stability is confirmed by the examination of the elastic constant. Based on the results, Ca₃AsBr₃ and Ca₃AsI₃ all demonstrate semiconducting behavior, with corresponding bandgaps energies of 2.45 and 1.94 eV respectively. Their corresponding bandgap energies and significant optical absorption make them great options for photovoltaic and optoelectronic applications. Enhanced Ca₃AsX₃ utilization in thermoelectric devices is demonstrated by the figure of merit, Seebeck coefficient, power factor PF, and other thermoelectric characteristics. Ca₃AsX₃(X = Br, I) are advantageous in the solar industry due to its external quantum efficiency and short-circuit current of 13 and 20.66 mA.cm⁻² respectively. The effect of temperature on the compound's entropy, free energy, enthalpy, and heat capacity is investigated in the study. This implies that Ca₃AsX₃(X = Br, I) compounds may open up new avenues for thermoelectric, optoelectronic, and photovoltaic system research.