Combined density functional theory and boundary element methods study on optical and electronic properties of interfacial Au/TiO2 defects

This study investigates the optical and electrical properties of Au/TiO₂ nanoparticles with different sizes and defects by combining micro- and macro-scale simulations through density functional theory (DFT) and boundary element method (BEM), respectively. The O-vacancy in the sample enhances the bonding and the electron transfer at the Au/TiO₂ perimeter zone, as indicated by the binding energy and charge density difference in DFT calculations, respectively. BEM simulation indicates a stronger electromagnetic field in the Au/TiO₂ interface of the sample with O-vacancy. DFT calculations demonstrate that the optical absorption of Au/TiO₂ in the ultraviolet range is well described by the absorption coefficient spectra, whereas the BEM results well describe the range of the surface plasmon resonance absorption of Au/TiO₂ in the wavelength range of 480–550 nm through the absorption cross-section. This study demonstrates the combined role of DFT and BEM in studying the electrical and optical properties of the nanocrystal system.