Enhanced Photocatalytic and Antibacterial Ability of Cu-Doped Anatase TiO₂ Thin Films: Theory and Experiment

Multifunctional thin films which can display both photocatalytic and antibacterial activity are of great interest industrially. Here, for the first time, we have used aerosol-assisted chemical vapor deposition to deposit highly photoactive thin films of Cu-doped anatase TiO₂ on glass substrates. The films displayed much enhanced photocatalytic activity relative to pure anatase and showed excellent antibacterial (vs Staphylococcus aureus and Escherichia coli) ability. Using a combination of transient absorption spectroscopy, photoluminescence measurements, and hybrid density functional theory calculations, we have gained nanoscopic insights into the improved properties of the Cu-doped TiO₂ films. Our analysis has highlighted that the interactions between substitutional and interstitial Cu in the anatase lattice can explain the extended exciton lifetimes observed in the doped samples and the enhanced UV photoactivities observed.