Comparative study of conduction-band and valence-band edges of TiO2, SrTiO3, and BaTiO3 by ionization potential measurements

Here, we report the energy positions of the conduction-band and valence-band edges of anatase titanium dioxide (TiO2), strontium titanate (SrTiO3), and barium titanate (BaTiO3). From the photoelectron yield spectra, the ionization potentials of anatase TiO2, SrTiO3, and BaTiO3 were estimated to be ca. 7.25, 6.90, 7.05 eV, respectively, which correspond to the top of the valence band of each titanium oxide. From these data and their band gaps, it was found that the bottoms of the conduction bands of SrTiO3 and BaTiO3 are positioned above that of anatase TiO2 by 0.40 and 0.23 eV, respectively. (C) 2017 Elsevier B.V. All rights reserved.