Hydrothermal Preparation Of Cesium Tungsten Bronze Nanopowders And Their Applications In The Field Of Transparent Heat-Shielding Glass Coating

With the rapid development of society,energy saving and reduction of pollutant emissions have become a common concern.In addition,due to the increasing popularity of cars,automotive glass(auto glass)as the main channel for energy and light exchange between the inside and the outside of cars,puts forward higher requirements for glass surface functionalization.Auto glass is required not only to isolate ultraviolet light,but also to isolate near infrared(NIR)light to achieve heat insulation and reduce energy consumption.Transparent heat-shielding coating with a high transmittance of visible light as well as with a high absorption of NIR light is of great significance for energy-saving and environmental protection,especially for applications of automotive and architectural windows.Cesium tungsten bronze(CsxWO3)is a kind of non-stoichiometric semiconductor material with narrow band gap and exhibits high transparence of visible light and intense absorption for NIR light with wavelength longer than 1100 nm.It also has the advantages of low price and no toxic elements,so it’s expected to be applied as transparent insulation coating instead of ITO and ATO materials.In this thesis,under the application background of transparent insulation coating for auto glass,CsxWO3 nanoparticles were successfully synthesized via a hydrothermal method using sodium tungstate and cesium carbonate as raw materials,and citric acid or D-malic acid as reducing agents.The effects of Cs/W(molar ratio),reducing agents,hydrothermal temperature and hydrothermal time on the crystallinity,morphology and absorbance of the products were systematically studied.The results show that the sample with n(Cs)/n(W)= 0.5 promotes formation of hexagonal Cs0.32WO3 with high crystallinity during hydrothermal synthesis.Moreover,with increasing reaction time,the morphology of the sample changes from irregular-shaped nanoparticles to rod-like nanoparticles.For as-prepared CS0.32WO3 powders,NIR absorption increases with the increase of crystallinity,moreover,NIR absorption increases largely when the CS0.32WO3 nanoparticles with rod-like morphology are formed.In this thesis,the transparent heat-shielding glass coating were prepared using as-prepared CS0.32WO3 nanoparticles as raw materials.The dispersion process of CS0.32WO3 nanoparticles and the effects of the factors of adding amount of CS0.32WO3 nanoparticles and coating thickness on the heat insulation performance of heat-shielding glass coating were explored.The mathematical models of optical properties with adding content of CS0.32WO3 nanoparticle and the thickness of the coating were obtained by a lot of experiments.A heat-shielding glass coating with excellent optical properties could be obtained with the addition of CS0.32WO3 dispersions at 6%and the coating thickness in the range of 4.6～5.1 μm.The transmittance ofNIR light is reduced to 10.2%,and the transmittance of UV light is reduced to 0.4%,and its transmittance of visible light(71.6%)is within the limit of auto glass regulations.At present,this optical property is at a leading position in auto glass industry,showing a good application prospect in the field of automotive and building glass.