Preparation And Properties Of Low-e Film

Widely used in the construction industry, glass is vital for the country and its quality has direct influences on our life.Ordinary glass has high emissivity and no-selectivity for light spectrum, so it is weak in heat preservation. This makes it one of the main leaking sources in building energy holding. The energy that runs away through windows occupies up to about 40% out of the total leaked energy in buildings. So the glass really plays an important role in energy saving.Since 1970s, the world energy crisis has been more and more serious. How to save energy has aroused high attention in every country. In the past 20 years, a low emissivity film (Low-E film) has been widely used in architecture and automobile industries. Glasses deposited with Low-E films can reflect infrared and ultraviolet while having high transmittance of visible light.Low-E films have two categories: hard and soft films. At present, most of the national factories produce hard low-E films. It has low costs but poor performances. So it is hard to fit the demands of advanced usage.This paper designs and prepares Low-E films with high-performance, and the main work is as follows:1. Introduce new researches and method of how to prepare Low-e films. Compare the two categories of Low-E glasses.2. Design the structure of high performance Low-E film including its material and thickness of every layer according to basic optical theory. Carry out an innovative work to calculate its optical performance by characteristic matrices and optical admittance. Compare the results with those we get by traditional measurement.3. Prepare Low-E films with RF magnetron controlled reactive sputtering. The result shows that in the visible region (380nm-780nm), the highest transmittance is 82.4% while the average value is 75%. In the NIR region (780nm-2500nm), the average transmittance is 16.2%. These characters can fit the demand of the glass used in architecture and cars, and also in other applications.4. We novelly use the material Titanium as protective layer to solve the problem that Ag layer would disappear when depositing the second TiO₂ layer. As the protective layer, Ti does not increase the number of targets so as to lower the costs. The thickness of the protective layer Titanium is adjusted by controlling of sputtering time. Results shows the Low-E films get the best optical character when the sputtering time of Titanium is 20 seconds5. We novelly proposed a new transmittance quality factor Q=(?)_max·((?)_VIS-(?)_?NIR) to evaluate the performances of Low-E films, which makes it easier to judge the qualities of Low-E film.6. The photocatalysis of Titanium dioxides is researched and introduced into Low-E films. Sb-doped TiO₂ thin films are prepared. Its photocatalysis andhydrophilicity are measured. The novel use of TiO2 increases the utilities of Low-E glasses. And this method has not been reported yet.