Tracking Ultrafast Interfacial Dynamics of Charge Transfer at the TiO ₂ Solid–Liquid Interface Using Time-Resolved Soft X-ray Absorption Spectroscopy

Despite the enormous efforts during the last decades, the measurement of exact charge transfer dynamics between dispersed nanomaterials and molecules solvated in liquid still remains challenging. This study elaborates on the interface of anatase TiO2 nanoparticles dispersed in pure water and in ethanol–solvated water, offering a unique opportunity to elucidate photoexcited charge transfer dynamics at the solid–liquid interfaces. Direct evidence of charge transfer from donor- or acceptor-type defect sites of TiO2 to ethanol-related species was observed with time constants of 186 ps.