Relaxation of photoexcited gold nanoparticles in an aqueous colloid and mesoporous TiO 2 films: Influence of the interface

The dynamics of relaxation processes for single-type Au nanoparticles in the form of aqueous colloid and nanoparticles embedded in a TiO 2 film have been investigated by femtosecond laser photolysis techniques. It has been shown that the theoretical models successfully applied to the description of the shape and dynamics of the differential spectra induced by a femtosecond pulse in Au nanoparticles in a dielectric are not sufficient to describe the differential spectra in the case of Au nanoparticles embedded a wide-bandgap semiconductor matrix. Evidence is presented for electron transfer from Au to TiO 2 upon excitation of plasmon resonance in Au. In this case, the electron transfer between the Au nanoparticle and TiO 2 results in a change in the pattern of differential spectra and influences the time evolution of the pattern.