PHOTOINDUCED HYDROPHILICITY AND PHOTOCATALYTIC PROPERTIES OF Nb205 THIN FILMS

摘要

Self-cleaning properties can be achieved by designing nanostructured superhydrophobic surfaces that repel dirt or alternatively by superhydrophilic coatings that can decompose organic matter through photocatalytic processes. While the photocatalytic properties and the related photoinduced hydrophilicity of Ti02 have been widely investigated, niobium pentoxide (Nb205) remains as a less investigated but promising material for transparent coatings with self-cleaning properties. In this work, Nb2Os thin films were fabricated by the decomposition of a molecular precursor [Nb(0'Pr)5]2 in a low pressure chemical vapor deposition (LPCVD) reactor at different substrate temperatures (500-1000 °C). Larger crystallites with preferred needle-like textures were observed in Nb205 deposits obtained at higher temperatures (> 800 °C), whereas smoother films were observed in the lower temperature regime suggesting the change in the balance of forces and growth kinetics. We report here on the wetting and photocatalytic properties of CVDgrown Nb205 thin films and correlate their functional properties with the surface morphology in order to demonstrate the potential of Nb2Os coatings in smart window and self-cleaning applications.