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Photoluminescence of TiO2: Effect of UV Light and Adsorbed Molecules on Surface Band Structure

Author:
Stevanovic, Ana, Büttner, Michael, Zhang, Zhen, Yates, John T.
Source:
Journal of the American Chemical Society 2012 v.134 no.1 pp. 324-332
ISSN:
1520-5126
Subject:
Fourier transform infrared spectroscopy, adsorption, ammonia, carbon monoxide, oxygen, photoluminescence, titanium dioxide, ultraviolet radiation
Abstract:
The photoluminescence (PL) of TiO₂ at 529.5 nm (2.34 eV) has been found to be a sensitive indicator of UV-induced band structure modification. As UV irradiation occurs, the positive surface potential changes and shifts the depth of the depletion layer. In addition, reversible band bending due to the adsorption of the electron-donor NH₃ and CO molecules has been observed in measurements combining PL with FTIR surface spectroscopy. It has been found that the O₂ molecule acts in two ways: as a reversibly adsorbed electron-acceptor molecule and as an irreversibly adsorbed molecule that heals natural oxygen vacancy defects in the near-surface region.
Agid:
5384698