Park, Sang Han Katoch, Abhishek Chae, Keun Hwa Gautam, Sanjeev Miedema, Piter Cho, Sang Wan Kim, Minseok Wang, Ru-Pan Lazemi, Masoud de Groot, Frank Kwon, Soonnam 2024-01-19T12:02:41Z 2024-01-19T12:02:41Z 2022-05-27 2022-05 2041-1723 https://pubs.kist.re.kr/handle/201004/115219 Direct and real-time observation of the excess holes in an element-specific and energylevel-specific manner is a challenging task. Here the authors present a complete hole dynamics of photo-excited anatase TiO2 with 100 femto-second resolution. Carrier dynamics affects photocatalytic systems, but direct and real-time observations in an element-specific and energy-level-specific manner are challenging. In this study, we demonstrate that the dynamics of photo-generated holes in metal oxides can be directly probed by using femtosecond X-ray absorption spectroscopy at an X-ray free-electron laser. We identify the energy level and life time of holes with a long life time (230 pico-seconds) in nano-crystal materials. We also observe that trapped holes show an energy distribution in the bandgap region with a formation time of 0.3 pico-seconds and a decay time of 8.0 pico-seconds at room temperature. We corroborate the dynamics of the electrons by using X-ray absorption spectroscopy at the metal L-edges in a consistent explanation with that of the holes. English Nature Publishing Group Direct and real-time observation of hole transport dynamics in anatase TiO2 using X-ray free-electron laser Article 10.1038/s41467-022-30336-1 1 Nature Communications, v.13, no.1 Nature Communications 13 1 Y scie scopus 000792848500016 Multidisciplinary Sciences Science & Technology - Other Topics Article NANOCRYSTALLINE TIO2 NANOPARTICLES SEPARATION OXIDATION