V.J. Rico, C. López, A.I. Borrás, J.P. Espinós, A.R. González-Elipe
Solar Energy Materials & Solar Cells, 90 (2006) 2944-2949
doi: 10.1016/j.solmat.2006.05.005

Wide band gap semiconductor oxides such as TiO₂, Ta₂O₅, ZnO, indium–tin oxide, InTaO₄ or In₂O₃ are materials with water contact angles in dark between 60° and 130°. The present investigation shows that thin films of these oxides become hydrophilic when they are irradiated with ultraviolet light. This finding indicates that the transformation of the wetting properties of illuminated wide band gap oxides is a common phenomenon not restricted to TiO₂. An additional evidence found for ZnO and InTaO₄ is that the water contact angle decreases by 30°/40° when they are irradiated with visible light.