Development of multifunctional photoactive self-cleaning glasses

Glasses for architecture must have many functions in addition to their transparency. For example, the glasses with the functions, of self-cleaning, light control, UV reduction, anti-bacterial, energy conversion, and so on, will be used in buildings in the near future. This paper reviews some results on multifunctional photoactive glasses based on multi-layer coatings containing TiO2 film and other functional coatings developed by us recently. The self-cleaning of glasses can be realized by coating the photoinduced super-hydrophilic nanoporous thin films based on TiO2 photocatalysts via sol–gel route. A new method to enhance the photocatalytic activity of TiO2 thin films direct coated on soda-lime glass was developed by treating the films in acidic solutions. The films also have good photoinduced anti-bacterial properties. The doping of a small amount of silver into the TiO2 porous film can enhance its anti-bacteria effect without UV light irradiation. The TiO2 thin films by appropriate heat-treatment can operate as self-cleaning glass in the visible light region. The UV reduction self-cleaning glasses are prepared by magnetron sputtering two layers of TiO2–CeO2 and TiO2 thin films on soda-lime glasses. The TiO2–CeO2 thin films can cut all of UV light through adjusting the ratio of TiO2 and CeO2. The TiO2/TiN/TiO2 type multi-layer coated on glass substrate can act as low-E self-cleaning glass. The potential water-repellent coating based on TiO2 is discussed finally.