Ultrafast plasmon induced electron injection mechanism in gold–TiO2 nanoparticle system

Publication date: June 2013 Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 15 Author(s): Luchao Du , Akihiro Furube , Kohjiro Hara , Ryuzi Katoh , Masanori Tachiya To study plasmon-induced charge transfer mechanism between an excited gold nanoparticle (NP) and a TiO2 NP, which can be applied to solar cell and photocatalyst technologies, ultrafast femtosecond visible-pump/infrared-probe transient absorption spectroscopy was utilized to explore charge separation and recombination dynamics in gold–TiO2 NP systems. In this review, our recent works are summarized. TiO2 NPs of different diameters were chosen as electron acceptors for a gold NP donor with a 10-nm diameter. Electron transfer from gold NPs to the conduction band of TiO2 was observed by the transient absorption of electrons in the conduction band of TiO2 at 3440nm after optical excitation of the surface plasmon band of gold NPs. By using a reference of Ru-complex dye sensitized TiO2 film, the occurrence of ultrafast electron injection from gold NPs to TiO2 NP film was clearly proved. It was found that electron injection was completed within 50fs and the electron injection yield reached 20–50% under 550nm excitation. The excitation wavelength dependence between 400 and 680nm suggested that there were two pathways for the injection: one was through direct electron-hole generation, and the other seemed to relate to enhanced electric field by plasmon. The charge recombinati...
Source: Journal of Photochemistry and Photobiology C: Photochemistry Reviews - Category: Chemistry Source Type: research