Preparation, Structure And Optical Absorption Properties Of Ag, CuO/SiO₂ Nanocomposite Films

It was well known that the research of new nanomaterial system, especially the design of nanocomposite system, has become the focus of nanomaterial science and technology. Nanocomposite film is one of nanocomposite materials that have a widely applying future. Because the changes of nanoparticles have evidently effects on the properties of nanocomposite film, it is easy to realize the tailoring of its functional properties. In this paper, the Ag, CuO/SiO2 nanocomposite films were prepared through sol-gel method and reduced under hydrogen atmosphere. The microstructure and properties of the composites were characterized by X-ray diffractometer (XRD), specific surface area and porosity instrument, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and UV-VisNir spectrophotometer. The most important factors of sol-gel processing that affect the resulting nanocomposite films' qualities were discussed sufficiently and the most reasonable ratio of every component was recommended. The optical absorption properties of every sample were discussed in detail. About the Ag/SiO₂ film, its optical absorption peak remarkably red-shifted (lower energy) and the full width at half maximum decreased with increasing the doped composition and reducing temperature. About the CuO/SiO₂ films, the optical absorption edge of 0.05CuO/SiO₂ treated at 300℃, 400℃, 500℃ in atmosphere can well followed the expression of semiconductor with indirect-band gap those of 0.02CuO/SiO₂ 0.05CuO/SiO₂ 0.1CuO/SiO₂ treated at 800℃ in atmosphere can well followed the expression of semiconductor with direct-band gap. The reasons of these phenomena were discussed by Mie theory.