SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 37: Poster: Ultrafast Electron Dynamics at Surface and Interfaces II
O 37.4: Poster
Dienstag, 28. März 2023, 18:00–20:00, P2/EG
Formation mechanism of defect levels in rutile TiO2(110) — •Xiang Zhang, Lukas Gierster, and Julia Stähler — Humboldt-Universität zu Berlin, Institut für Chemie
The electron dynamics at TiO2 surfaces have been widely studied as TiO2 is a prototypical photocatalyst. Recent studies have specifically addressed the Band Gap State (BGS) at 0.8 eV below the Fermi level and have revealed its role as a trapping center for electrons in the conduction band of rutile TiO2(110) (with a trapping time of around 45 fs) [1]. However, the origin of the BGS itself remains debated. Using time-resolved photoelectron spectroscopy, we show here that the BGS must be - at least partially - due to long-lived (>5 µs) photoexcited charge carriers which form a photostationary state in pump-probe experiments. The potential formation mechanism of the BGS and implications of this state for previous time-resolved experiments are discussed.
Reference:
[1] Zhang et al. J. Phys. Chem. Lett. 10(52) (2019).