Electronic and Structural Properties of Sn_xTi_1−xO₂(0.0 ≤x≤ 0.1) Solid Solutions

The electronic and structural properties of dilute solid solutions of SnO 2 in TiO 2 have been investigated. Samples of Sn x Ti 1− x O 2 with 0.0 ≤ x ≤ 0.1 (i.e., 0−10% Sn doping) were prepared by solid state reaction of SnO 2 and TiO 2 powders at 1200 °C followed by rapid quenching. Narrowing of the bandgap at low Sn doping level was observed through both diffuse reflectance spectroscopy and valence band photoemission spectroscopy. This provides an explanation of the visible light photocatalytic activity previously reported for this system. X-ray diffraction showed a positive deviation of the lattice parameters from Vegard’s Law, whereas Raman spectra revealed a red-shift in the E g and B 1g peaks and a blue-shift in the A 1g peak with increasing Sn content.