Influence of Tb-dopant on water adsorption and wettability of TiO2 thin films

In this work wettability and adsorption of OH^- groups and H₂O particles on the surface of TiO₂ thin films doped with different concentration of Tb have been described. Thin films were manufactured by magnetron sputtering process. The particles were sputtered from metallic Ti-Tb target under low pressure of oxygen gas. The results of structural investigation (X-ray diffraction measurements) have shown that Tb-dopant has meaningful influence on structure of prepared thin films. The role of terbium on the surface adsorption of nanocrystalline TiO₂:Tb thin films was revealed from X-ray photoelectron spectroscopy measurements. The wetting angle measurements and XPS results have shown that TiO₂:Tb (0.4 at. %) thin film, with anatase structure, had the highest adsorption ability and the smallest wetting angle. Moreover, the wettability of this film was almost as high as in the case of super-hydrophilic films. TiO₂:Tb (2.6 at. %) thin film had rutile structure, low adsorption ability and the highest value of wetting angle as-compared to other manufactured films.