Fast and Slow Time-Scale Effects of Photoinduced Surface Oxygen Vacancies on the Charge Carrier Dynamics of TiO₂

The migration of charge carriers (e.g., electrons and holes) in metal oxides, such as TiO2, plays a vital role in (photo)catalytic applications. Nevertheless, photoinduced surface oxygen vacancies (PI-SOVs), prompted by high-energy ultraviolet irradiation, can significantly alter the dynamics of the charge carriers. Here, we performed time-resolved atomic force microscopy measurements to quantitatively deliver effects of such surface defects on the dynamics of fast (i.e., electrons) and slow (i.e., holes) charge carriers of the TiO2 and TiO2/gold nanoparticle interface. Our results show that time constants and/or energy barriers associated with the migration of charge carriers change across the sample landscape due to PI-SOVs.