Enhancement of Photoexcited Charge Transfer by {001} Facet-Dominating TiO₂ Nanoparticles

The recent discovery of a synthetic method for chemically reactive {001} facet-dominating TiO 2 nanoparticles using hydrofluoric acid provided a new aspect of interfacial chemistry in photo catalysts, batteries, and photoelectrochemical cells using TiO 2 . We reveal the effects of the reactive {001} facet on the photoexcited charge transfer from organic fluorophores, 9-substituted anthracene derivatives (An–X; X = H and COOH) and tetracene, to TiO 2 nanoparticles by differing the fraction of {001} facet. The kinetic analysis of the fluorescence quenching by TiO 2 nanoparticles based on Stern–Volmer relation is employed to estimate the quenching rate constant as a function of the fraction of {001} facet. The results imply a significant enhancement of the photoexcited charge transfer from fluorophores to TiO 2 nanoparticles by the reactive {001} facet with a factor of more than 10 in the quenching rate constant at maximum.