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

Thin solid films composed from monodispersed cupric oxide particles with average size about 0.06 mum and narrow distribution of sizes have been prepared by dip-coating technique. The thermal decomposition method has been applied for the preparation of particulate sols. Sols and the corresponding gels have been made from cupric acetate precursor and citric acid as chelating agent. Sols showed a tendency for gelling during 48 h when kept at 70-degrees-C. X-ray diffraction, scanning electron microscopy, thermogravimetric analysis and Fourier transform infrared spectroscopy have been used for studying the structural features of 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 different 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 films are obtained per dipping. A potential use of the CuO coatings on glass is in window glazing with shading properties for the luminous part of the solar radiation.