Optimization of phase formation and photocatalytic performance in TiO2 thin films through ytterbium and erbium doping in sol–gel dip-coating process

Abstract

This study explores the phase formation, electrochemical properties, and photocatalytic performance of titanium dioxide (TiO2) thin films doped with either ytterbium (Yb) or erbium (Er) via a sol–gel dip-coating process. Thin films were annealed at 500 °C to predominantly form anatase structures, with varying doping concentrations analyzed to assess their impact on phase stability and charge transport properties. Higher dopant levels resulted in increased anatase content and reduced crystallinity, enhancing electron–hole separation and charge mobility, while lower dopant levels promoted the anatase-to-rutile transition. The electrochemical performance was evaluated by the photocatalytic degradation of methylene blue (MB), where doped films demonstrated significantly improved efficiency compared to undoped films, attributed to enhanced surface adsorption and charge separation at anatase–rutile interfaces. The incorporation of rare-earth dopants was found to introduce intra-bandgap states, facilitating enhanced electron transport and improving the overall electrochemical activity of TiO2 films. These findings suggest that rare-earth doped TiO2 thin films hold promise for applications in solid-state electrochemical devices and environmental remediation technologies, particularly in the catalysis and degradation of organic pollutants.