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Photoluminescence studies of nitrogen-doped TiO2 powders prepared by annealing with urea |
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| Authors: | T Kawai Y Kishimoto K Kifune |
| Institution: | 1. Department of Physical Science, Graduate School of Science , Osaka Prefecture University , Gakuen-cho 1-1, Naka-ku, Sakai City , Osaka 599-8531 , Japan buri@p.s.osakafu-u.ac.jp;3. Department of Physical Science, Graduate School of Science , Osaka Prefecture University , Gakuen-cho 1-1, Naka-ku, Sakai City , Osaka 599-8531 , Japan;4. Department of Physical Science, Graduate School of Science , Osaka Prefecture University , Gakuen-cho 1-1, Naka-ku, Sakai City , Osaka 599-8531 , Japan;5. Faculty of Liberal Arts and Sciences , Osaka Prefecture University , Gakuen-cho 1-1, Naka-ku, Sakai City , Osaka 599-8531 , Japan |
| Abstract: | Photoluminescence and excitation spectra have been investigated for undoped and nitrogen-doped TiO2 powders at low temperatures. A broad luminescence band peaking at 2.25?eV is observed in the undoped TiO2 powders. The 2.25?eV luminescence band exhibits a sharp rise from 3.34?eV in the excitation spectrum reflecting the fundamental absorption edge of anatase TiO2. On the other hand, the N-doped TiO2 powders obtained by annealing with urea at 350 and 500°C exhibit broad luminescence bands around 2.89 and 2.63?eV, respectively. The excitation spectra for these luminescence bands rise from the lower energy side of the fundamental absorption edge of anatase TiO2. The origin of the luminescence bands and N-related energy levels formed in the band-gap of TiO2 are discussed. |
| Keywords: | anatase TiO2 localized states luminescence properties sol-gel method brookite phase rutile phase |