Abstract
We report herein the investigation of a novel non-adiabatic optical near-field (ONF) excitation on nanostructured TiO photo-anode. The usage of ONF allows the transition to the dipole forbidden phonon states, which is called the phonon-assisted ONF transition, and hence allows us to excite TiO by sub-bandgap photon. Here, we investigated the usage of ONF to induce the photocatalytic activity of TiO with visible light instead of conventional UV light. By introducing nanostructure into TiO photo-anode to generate optical near-field at the surface of electrode, we confirmed the enhancement of photo current in the visible range, and this current is attributed to the phonon-assisted ONF excitation. This study should lead to a novel approach to excite TiO by sub-bandgap photon, consequently improve its visible-light response photocatalytic performance. It also suggest that this kind of nanostructured semiconductor photocatalyst have promising properties for hydrogen production from water splitting.