DFT exploration of elastic, optoelectronic, and thermoelectric properties of stable and eco-friendly double perovskites Cs2YAuX6 (X=Cl, Br) for green energy applications

Abstract

In the current investigation, we have implemented first-principles calculations to examine the structural, elastic, electrical, and optical characteristics of Cs2YAuX6 (X = Cl, Br). The structural, thermal, and mechanical stabilities are assured by the tolerance factor, formation energy, and Born-Huang criteria. The elastic constants data demonstrates that both materials have a ductile nature and are flexible enough for use in foldable photovoltaic devices. In addition, the computed bandgap values for Cs2YAuCl6 and Cs2YAuBr6 are 2.2 and 2.0 eV, respectively, which demonstrates the indirect semiconducting nature. The low effective masses of Cs2YAu Cl6 and Cs2YAuBr6 make them useful materials for carrier conduction. The analysis of optical characteristics also reveals that both materials are very effective at absorbing light throughout the ultraviolet–visible spectrum. The higher power factor as well as minimal thermal conductivity result in significant figure of merit values up to 0.78 and 0.82. These results indicate the considerable potential of these materials for use in photovoltaic cells and thermoelectric devices.