Although double halide perovskites have garnered significant attention as environmentally benign and structurally versatile alternatives to lead-based counterparts, the optoelectronic behavior of the \(\hbox {Rb}_2\) \(\hbox {YAuX}_6\) (X = F, Cl, Br, I) remain underexplored. Given the favorable bandgaps 1.47 eV, 2.04 eV, 1.63 eV, and 1.13 eV (GGA) and 1.19 eV, 1.85 eV, 1.48 eV, and 0.94 eV (GGA+SOC) and stability often associated with gold-based perovskites, and the significant impact of spin-orbit coupling (SOC) owing to the presence of heavy elements including gold, theoretical calculations were performed using density functional theory on the double halide perovskite compound \(\hbox {Rb}_2\) \(\hbox {YAuX}_6\) (X = F, Cl, Br, I). We have found that the computed bandgaps and the most active optical absorption are within the Vis–UV range with an absorption coefficient \(\alpha \) > \(\hbox {10}^5\) \(\hbox {cm}^{-1}\) , suggesting that these materials are highly promising for the development of efficient and stable light-harvesting materials for next-generation solar energy technologies.
