Sol-gel Preparation And Properties Of Sb Doped SnO₂ Thin Films And Research Of Novel Energy Saving Coating Glass

In this thesis a comprehensive introduction of energy saving coating glass, especially low emissivity (Low-E) glass has been given including the development, energy saving characteristic, types and preparation methods. It shows that highly doped wide energy gap semiconductors(e.g. SnO2) has promising prospect as the film material of economical energy saving coating glass because of its excellent optical property, cheap cost and easiness to handle.Using metal salts SnCl2 ?2H2O and SbCh as precursors, thin films of antimony-doped tin oxide with good optical and electrical properties have been deposited by the sol-gel dip coating method. The sheet resistance can reach 144 Q/D, the number of carriers is about 6.53 X 1020cm"3 with mobility 3.02 cm2v~'s~', and the visible transmission is about 85 % with infrared reflection over 20% after the SnO2:Sb film has been treated under 500 癈 temperature, with Sb doping level 15%, dipping 5 times.It has been found that the heat-treatment temperature, film thickness and doping level have strong influence on the microstructure and composition of SnO2 films. The optimum heat-treatment temperature is about 450-500癈 , the film is composed with crystals and pores of nano-size, and higher temperature and thicker film can benefit the crystallization of SnO2 crystals. But too high thickness and doping level will do harm to the smoothness of film surface with doped impurity deteriorating the crystallization. The SnO2 crystals exist mainly as tetragonal rutile structure, despite of some rhombic SnO crystals.The electrical and optical behaviours of Sb-doped SnO2 thin films derived by sol-gel process have been investigated. It shows that SnO: film with suitable doping level (-15%) has favorable electrical conductivity, high transmittance and low reflection in visible light range. The infrared reflection rely much on the concentration and mobility of the carriers in the films. Improving the concentration and mobility of the carriers, decreasing the electrical resistivity will enhance of the infrared reflection of the SnO2 film.Based on these above, the SnO? single Low-E coating glass and SnO2/Si multilayer coating glass with energy saving property have been elaborated on float glass and Si-based coating glass using spin coating method. The experiment results of optical property and chemical stability show that combined with SnO2 thin film layer. the glass have improved its thermal insulation property and lead to energy saving ability to some extent. More than that, the transmittance and reflection in visible light range of this glass have been optimized.