报告题目: Charge Generation Dynamics in High Optical Absorbance Multilayer Film of Au and TiO2
报告人: Akihiro Furube, Tokushima University
Akihiro Furube has been a chair and professor in the Department of Optical Science, Tokushima University since 2015. He got his PhD degree in applied physics from Osaka University under the supervision of Professor Hiroshi Masuhara in 1999. As postdoctoral research positions from 1999 to 2001, he worked at Osaka University, University of Texas at Austin, Georgia Institute of Technology and Tokyo institute of Technology. In 2001, he became a Research Scientist in National Institute of Advanced Industrial Science and Technology AIST and in 2006 was promoted as a Senior Research Scientist. In 2008, he was appointed as an adjunct Associate Professor at the University of Tsukuba. His research theme is ultrafast charge transfer dynamics in nanomaterials using femtosecond spectroscopy.
Metal-insulator-metal MIM structure using gold nanoparticles, titanium dioxide TiO2, and gold Au film was fabricated. The optical absorption nature of the films in visible and NIR region with different TiO2 thickness were studied by steady-state extinction spectra and femtosecond transient absorption data. The extinction spectra of multilayer film showed the absorbance of the wide range of visible light. Further coating by Au film resulted in very broad absorption covering whole visible and NIR region. Transient absorption study proved that the generation of the conductive electrons by plasmon induced electron transfer from Au to the conduction band. The electron lifetimes in picosecond timescale depended on the film thickness of TiO2 layer, suggesting that thicker film is appropriate to obtain long-lived carriers.