1. Femtosecond time-resolved X-ray absorption spectroscopy of anatase TiO2 nanoparticles using XFEL
- Author
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Terumasa Ito, Shutaro Karashima, Tadashi Togashi, Kazuhiko Misawa, Naoya Kurahashi, Yuki Obara, Shigeki Owada, Tetsuo Katayama, Makina Yabashi, Junichi Nishitani, Yo-ichi Yamamoto, Toshinori Suzuki, Hironori Ito, Hiroki Tanaka, and Stephan Thürmer
- Subjects
Anatase ,Materials science ,Absorption spectroscopy ,Analytical chemistry ,02 engineering and technology ,010402 general chemistry ,medicine.disease_cause ,01 natural sciences ,Molecular physics ,law.invention ,law ,lcsh:QD901-999 ,medicine ,Instrumentation ,Spectroscopy ,X-ray absorption spectroscopy ,Radiation ,Free-electron laser ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Laser ,0104 chemical sciences ,Femtosecond ,lcsh:Crystallography ,0210 nano-technology ,Ultrashort pulse ,Ultraviolet - Abstract
The charge-carrier dynamics of anatase TiO2 nanoparticles in an aqueous solution were studied by femtosecond time-resolved X-ray absorption spectroscopy using an X-ray free electron laser in combination with a synchronized ultraviolet femtosecond laser (268 nm). Using an arrival time monitor for the X-ray pulses, we obtained a temporal resolution of 170 fs. The transient X-ray absorption spectra revealed an ultrafast Ti K-edge shift and a subsequent growth of a pre-edge structure. The edge shift occurred in ca. 100 fs and is ascribed to reduction of Ti by localization of generated conduction band electrons into shallow traps of self-trapped polarons or deep traps at penta-coordinate Ti sites. Growth of the pre-edge feature and reduction of the above-edge peak intensity occur with similar time constants of 300–400 fs, which we assign to the structural distortion dynamics near the surface., 光触媒ナノ粒子における光照射後10兆分の1秒での電子の動きをX線自由電子レーザーで観測. 京都大学プレスリリース. 2017-07-06.
- Published
- 2017
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