Preparation And Study Of TiO₂ Films And Doped TiO₂ Films By Continuous-Fast Atmospheric Pressure Chemical Vapor Deposition

In this paper, a comprehensive introduction of TiO₂, including its background and mechanisms of photocatalysis & hydrophilicity, had been given. A comparison between different preparation methods and influencing factors on T1O2 films' photocatalysis and hydrophilicity had been discussed.At present in China, the study of online deposition of TiO₂ films is still under exploration. For this, a self-designed apparatus was used to simulate the online deposition on float glass production line. This apparatus can deposit TiO₂ films continuously on the moving glass substrates with short deposition time and high deposition rate.Combined with the float glass production line, this paper put forward an aim to prepare photocatalytic & hydrophilic TiO₂ films on float glass substrates via TTIP by the atmospheric pressure chemical vapor deposition (APCVD). Based on these, the F doped TiO₂ films were prepared by adding TFE into the precursors.By the characterization of the film's crystal structure, thickness and surface topography etc., the correlations between key preparation parameters (substrate temperature, substrate moving speed, total gas flow rate & precursor concentration) and the film's structures & properties were studied systematically . The study showed that:The film's photocatalysis was changed with the variations of its crystal structure, thickness and surface topography. Anatase TiO₂ films with higher crystallinity had a better photocatalysis than others'. The film's photocatalysis reached its maximum in an optimal film thickness - 300nm. The film with tough and dense surface had better photocatalysis.For the film's hydrophilicity, it was also influenced by the film's crystal structure, thickness and surface topography. Anatase TiO₂ films with higher crystallinity had a better hydrophilicity than others'. The hydrophilicity of films did not depend on the thickness of films thicker than a threshold value. The smooth and homogenous surface of the TiO₂ film showed to favor water spreading.The best preparation parameters for depositing TiO₂ films are: when the substrate moving speed was 1.5 m/min, substrate temperature was 580℃, total gas flow rate was 26.34 L/min and the concentration of TTIP was 1.0 %. When the substrate moving speed was 6.0 m/min, the best total gas flow rate was 26.34 L/min.Additionally, the relation between doping gas (TFE) flow rate and the TiO₂ film's structures & properties was discussed. The formation of anatase phase was suppressed by adding TFE. When the TFE flow rate was 5.94 L/min, both the photocatalysis and hydrophilicity of TiO₂ films reached the maximum and were better than pure TiO₂ films'.It shows that the fast APCVD apparatus, which simulate online coating on float glass production line, can effectively prepare TiO₂ coated glass. And this work could provide significant preparation parameters and theoretical guides for the industrial utilization.