Preparation, Structure And Properties Of The Multifunctional Coating Glasses

A comprehensive introduction of solar control (Sun-E) coating glass, low emission (Low-E) glass and self-cleaning coating glass has been given in this paper. Aimed at compositing the function mentioned above, Low-E/Sun-E and self-cleaning/Low-E multifunctional films were prepared by the method of atmospheric pressure chemical vapor deposition (AP-CVD), which is applicable to deposit films on-line. And the relations between the preparation conditions and the structure, morphology and properties of the composite films were analyzed by the methods such as X-ray diffraction (XRD), transmission electron microscope (TEM), field emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS), atomic force microscope (AFM) and ultraviolet & visible absorption spetrum (UV-VIS). Using monobutyltin trichloride (MBTC) as the precursor, trifluoroethanol (TFEA) as a new dopant, and water (H₂O) as a catalyzer, the SnO₂:F/(Si/SiC) composite films were prepared by depositing fluorin doped tin dioxide on the Si/SiC coating glass substrates, with the method of atmospheric pressure chemical vapor deposition (APCVD). The structure, morphology and properties of SnO₂:F/(Si/SiC) composite films varied with concentration of MBTC, TFEA and H₂O observably. It was observed that the preferred orientation of SnO₂:F thin films mainly depended on the concentration of precursor and catalyzer, but not that of dopant. Visible and near infrared reflectivity of the composite films were observably higher than that of the single SnO₂:F thin film, and the composite films had the function of heat insulation. At the concentration of MBTC=1.8mol%, TFEA=35wt%, and H₂O=1mol%, the square resistance of composite film had the minimum value 21Ω/â–¡ , and the mid-far infrared average reflectance reached 81%, that is, the film had a good Low-e function. So the multiplicity of the functions of Low-E and Sun-E could be realized to some extent. In addition, analysing the cross section of SnO₂:F/(Si/SiC) composite film by EDS line-scanning, it was found that there existed an inter-diffusion between the multi-films of ions such as Sn, Si and C, and alkali metals ions such as Na may diffuse into Low-E functional layer, which can reduce the Low-E function. Meanwhile, using titanium (IV) isopropoxide as the precursor, TiO₂/SnO_:F composite films were prepared by depositing titanium films on SnO₂:F coating glass substrates, with the method of APCVD. It was found that the surface roughness of TiO₂/SnO₂:F composite films increased and TiO₂ transformed from amorphism into anatase as the temperature increased. Needle structure was observed in the composite film at 480℃, and the photocatalytic efficiency and hydrophilisy increased at the meanwhile. When temperature went on increasing, TiO₂ began to transform from anatase to rutile, and the needle structure disappeared, but the photocatalytic efficiency and hydrophilisy still increased. When the temperature achieved to 580℃, TiO₂ became rutile in large part, which led to the decrease of the photocatalytic efficiency and hydrophilisy. The thickness of TiO₂ thin film decreased as the transporting velocity of substrate increased. It resulted in the decrease of the photocatalytic efficiency and hydrophilisy. The interface of TiO₂/SnO₂:F composite film was analyzed by the same methods mentioned above. It was found that Sn ions diffused deep into TiO₂ layer, but Ti ions only diffused to the surface of SnO₂:F layer. The optical transmittance in the visible region of the composite films varied in the range of 60-90%, which was suitable for the daylighting request of buildings. When the substrate temperature was 430℃, and the substrate velocity was 1.5m/min, the composite film maintained some photocatalysis and hydrophilisy besides nicer Low-E function.