In situ EPR studies of electron trapping in a nanocrystalline rutile

I. Ross Macdonald, Russell F. Howe, Xinyuan Zhang, Wuzong Zhou

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Abstract

This paper describes an in situ EPR study of electron trapping in a nanocrystalline rutile material. Irradiation at 4K with broad-band UV-Vis light gives weak signals of trapped electrons. When irradiation is stopped, intense Ti3+ EPR signals appear, which can be removed again by resuming the irradiation. It is proposed that under irradiation there is a dynamic equilibrium established between creation of conduction band electrons, trapping of electrons, and excitation from trap sites back into the conduction band. When irradiation is stopped, conduction band electrons are trapped and remain so in the dark. Some initial results on the temperature and wavelength dependence of these processes are presented. (C) 2010 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)238-243
Number of pages6
JournalJournal of Photochemistry and Photobiology. A, Chemistry
Volume216
Issue number2-3
Early online date30 Jul 2010
DOIs
Publication statusPublished - 15 Dec 2010

Keywords

  • rutile
  • EPR
  • trapped electrons
  • trap sites
  • charge-carrier dymanics
  • anatase TIO2 particles
  • mixed-phase TIO2
  • nanoparticles
  • semiconductor
  • absorption
  • powders
  • ESR

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