Charge Trapping Process in Photoexcited Nitrogen-Doped Titanium Oxides

Kosuke Sato, Ken Ichi Yamanaka, Shunsuke Nozawa, Hironobu Fukuzawa, Tetsuo Katayama, Takeshi Morikawa, Takamasa Nonaka, Kazuhiko Dohmae, Kiyoshi Ueda, Makina Yabashi, Ryoji Asahi

Research output: Contribution to journalArticlepeer-review

Abstract

We present a first-principles study on the structural changes induced by charge trapping that occurs after photoexcitation in nitrogen-doped titanium oxide (N-TiO2). The charge trapping site and the corresponding K edge EXAFS spectra of Ti atoms were predicted and compared with those obtained by an experiment under ultraviolet (UV) light excitation. The results indicate that charge trapping occurs in the neighborhood of the oxygen vacancy (O-vac) sites. Furthermore, our calculations show that the O-vac site significantly affects the EXAFS spectra, while substitutional nitrogen doping for an oxygen site in the vicinity of the O-vac site is insensitive in the EXAFS spectra. Based on this observation combined with the knowledge from previous experiments, we propose a charge trapping process where the UV light-excited electron migrates at the O-vac site in bulk (∼300 ps) while the visible light-excited electron (N 2p → Ti 3d) is immediately trapped at the O-vac site neighboring the N site (∼1 ps).

Original languageEnglish
Pages (from-to)10439-10449
Number of pages11
JournalInorganic chemistry
Volume59
Issue number15
DOIs
Publication statusPublished - 2020 Aug 3

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Fingerprint

Dive into the research topics of 'Charge Trapping Process in Photoexcited Nitrogen-Doped Titanium Oxides'. Together they form a unique fingerprint.

Cite this