STRUCTURAL AND OPTICAL CHARACTERIZATION OF CUO PARTICULATE SOLID FILMS AND THE CORRESPONDING GELS AND XEROGELS

Thin solid films composed from monodispersed cupric oxide particles wi th average size about 0.06 mum and narrow distribution of sizes have b een prepared by dip-coating technique. The thermal decomposition metho d has been applied for the preparation of particulate sols. Sols and t he corresponding gels have been made from cupric acetate precursor and citric acid as chelating agent. Sols showed a tendency for gelling du ring 48 h when kept at 70-degrees-C. X-ray diffraction, scanning elect ron microscopy, thermogravimetric analysis and Fourier transform infra red spectroscopy have been used for studying the structural features o f oxide coatings, xerogels and the corresponding intermediate stages. It was found that the gel and xerogel consist of copper complexes with ammonia (-NH3), hydroxo (-OH) and carboxylate (-COO) moieties in the form of bridges, thus making possible an interlinkage between differen t copper ion complexes. Optical spectra revealed that a reddish-purple coating is produced on glass by dip-coating method. The efficiency of dip-coating procedures is high since 0.040+/-0.005 mum thick CuO film s are obtained per dipping. A potential use of the CuO coatings on gla ss is in window glazing with shading properties for the luminous part of the solar radiation.