Hot electron transfer induced by surface Plasmon in Ag/TiO2 system

Abstract

Metal-semiconductor nanostructures are promising materials in plasmonic photocatalysis because the structures exhibit a pronounced surface plasmon absorption. The surface plasmon can induce charge transfer in metal-semiconductor system. Herein, we assembled Ag/TiO2 systems and measured ultrafast dynamics by femtosecond transient absorption spectroscopy. A bleach signal of Ag/TiO2 nanocomposites was observed, and the strong coupling of Ag/TiO2 nanocomposites resulted in the broadening of the surface plasmon band. In order to further elucidate the microphysical mechanism of charge transfer in Ag/TiO2 system, the ultrafast dynamics of the composite system were analyzed. The results show that hot electron injection is completed in 150 fs, and the charge recombination time constant is 3.2 ps. Hot electron transfer is beneficial to improve photocatalytic performance.