Investigation of Electronic, Mechanical, Optical, and Thermoelectric Characteristics of Halide Double Perovskites Na₂AuInZ₆ (Z = Cl, Br, and I) for Solar Cells and Renewable Energy Applications

This article explored the optoelectronic properties, mechanical characteristics, and thermoelectric features of halides double perovskites (DPH) Na₂AuInZ₆ (Z = Cl, Br, and I). This analysis of optoelectronic and thermoelectric features has been performed to suggest the capability for solar energy and thermoelectric device applications. These DPHs in the cubic phase are determined to be structurally stable by the computed structural and elastic attributes. The formation energy for each DPH is also calculated to verify thermodynamic stability. In addition, the ductile nature of these materials is suggested by the expected values of Pugh’s and Poisson’s ratios. The Tran-Bhala modified Becke and Johnson potential (TB-mBJ) has been utilized to estimate optoelectronic characteristics precisely. Electronic band structure simulations suggest these compounds have direct band gaps of 2.70 eV, 1.75 eV, and 0.46 eV and could be suitable for various optoelectronic applications. The optical properties in the incident light energy range of 0–6 eV have also been covered to analyze the potential for solar cells by examining absorption, reflectance, and loss of energy. Finally, the thermoelectric characteristics are determined by the effect of varying temperature. The power factor and figure of merit analysis suggest that these materials may be suitable for thermoelectric device applications. Hence, this study has comprehensively elaborated on the advantages of studying halides for sustainable energy technologies.