Computational insights into the structural, electronic, mechanical, and optical properties of Cu, Ge, and Au-doped CsTiO3 for optoelectronic applications

Abstract

The study of inorganic oxide perovskites (Cs_1-xCu_xTiO₃, CsTi_1-xGe_xO₃, Cs_1-xAu_xTiO₃; x = 0,0.50), using DFT employs GGA-PBE and LDA to analyze structural, electronic, mechanical, and optical properties. Investigated the lattice constants and bond length of pure CsTiO₃ and doped variants, exploring consequent modifications in electronic, optical, and mechanical behaviors. The theoretically determined lattice parameters and unit cell volume strongly agree with reported theoretical findings and provide a reference for future experimental validation. The mechanical characteristics are crucial for ensuring the structural stability of (Cu), (Ge), and (Au) doped materials and identifying ductile behavior. The computed results reveal that CsTiO₃ exhibits an indirect bandgap and displays optically inactive behavior. The bandgap of pure CsTiO₃ continuously reduced, resulting in a shift of Fermi energy level to the E_g. As the doping concentrations of (Cu), (Ge), and (Au) in CsTiO₃ are increased (x), the bandgap shifts from an indirect (M-G) to direct (M-M) nature and becomes optically active. Reducing the bandgap improves the absorption and optical conductivity. The energy range of 0–27 eV is used to compute optical parameters, including dielectric properties, energy loss functions, refractive index, conductivity, absorption coefficient, and reflectivity. Their exceptional properties highlight their potential in next-generation device technologies.