First-principles study of structural, mechanical, electronic, thermodynamical and optical properties of XGaO2 (X=Rb and Cs): Unlocking its green energy potential

Lead-free metal oxides are currently considered promising options for green energy harvesting, particularly as active semiconductors in photovoltaic cells and photocatalysts, which meet future generation energy demands. This research conducted a first-principles investigation into XGaO 2 (X= Rb and Cs) metal oxides. Here, density functional theory (DFT) simulations employed to evaluate the structural, mechanical, electrical, optical, thermodynamical, and photocatalytic characteristics of XGaO 2 . The materials XGaO 2 exhibits ductile in nature as well as anisotropic character. The studied materials exhibit stable structures with direct band gaps of 2.39 eV and 2.67 eV for RbGaO 2 and CsGaO 2 , respectively. Various optical parameters were predicted. The high optical conductivity and reflectivity in addition to the better dielectric constant of CsGaO 2 , reflect that this material could be a potential candidate in the field of optoelectronics device fabrication. The thermal impact on the heat capacity, entropy, enthalpy, and free energy was analyzed. The band edges of RbGaO 2 and CsGaO 2 showed that the materials have the precise oxidation and reduction potentials to break down contaminants in wastewater and generate hydrogen through water splitting. Thus, the finding of this research could be helpful to get more suitable devices for solar-driven H 2 generation via water splitting and dye degradation from wastewater.