Mechanisms of plasmon-induced charge separation and recombination at gold nanoparticle supported on different size TiO2 film systems

Luchao Du; Akihiro Furube; Kohjiro Hara; Ryuzi Katoh; Masanori Tachiya

doi:10.1117/12.756494

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4 January 2008 Mechanisms of plasmon-induced charge separation and recombination at gold nanoparticle supported on different size TiO₂ film systems

Luchao Du, Akihiro Furube, Kohjiro Hara, Ryuzi Katoh, Masanori Tachiya

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Proceedings Volume 6831, Nanophotonics, Nanostructure, and Nanometrology II; 68310W (2008) https://doi.org/10.1117/12.756494
Event: Photonics Asia 2007, 2007, Beijing, China

Abstract

Study of plasmon-induced charge transfer mechanism in gold-TiO₂ system is crucial and promising in the solar cell application. To investigate charge separation and recombination dynamics in gold/TiO₂ nanoparticle systems, we used ultrafast visible-pump/IR-probe femtosecond transient absorption spectroscopy method. In our experimental study, anatase TiO₂ with different particle size 9 nm and 20 nm were chosen as electron acceptors. Plasmon-induced electron transfer from the gold nanoparticle to the conduction band of TiO₂ was studied by optical excitation of the surface plasmon band of gold nanoparticle at 550 nm. The transient absorption kinetics were studied by probing at 3440 nm to observe intraband free electron adsorption in TiO₂. In our experimental results, electron injection was found to be completed within the apparatus time resolution (240 fs), the charge recombination decay within 1.5 ns was nonexponential. And when laser power changed from 0.5 μJ to 1.9 μJ, the recombination decay didn't depend on the excitation intensity. It is interesting that we found the measured back electron transfer kinetics up to 1.5 ns were strongly dependent on the particle size of TiO₂. The plasmon-induced charge transfer mechanisms will be discussed.

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Luchao Du, Akihiro Furube, Kohjiro Hara, Ryuzi Katoh, and Masanori Tachiya "Mechanisms of plasmon-induced charge separation and recombination at gold nanoparticle supported on different size TiO₂ film systems", Proc. SPIE 6831, Nanophotonics, Nanostructure, and Nanometrology II, 68310W (4 January 2008); https://doi.org/10.1117/12.756494

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