Atmospheric Pressure CVD Process for Preparing Fluorine-doped Tungsten Oxide Films

It is well-known in the glass art to coat glass sheets with metallic and/or dielectric materials to impart enhanced solar and optical properties to the glass sheets. For example, it is known to place multiple layers of metals and dielectrics onto glass to produce electrically conductive coatings which are transparent to visible light and yet highly reflective to infrared radiation. It is also known to deposit conductive metal oxides onto glass, such as fluorine-doped tin oxide, which are also highly reflective to infrared radiation.

Tungsten oxide is a transparent semi-conductor, which when doped with fluorine shows an appreciable increase in its infrared absorption and reflection. Hence, fluorine-doped tungsten oxide films are potential candidates as coatings on glass for solar control applications. By reflecting and/or absorbing energy in the infrared, these coatings when applied to glass reduce the energy influx into a building or motor vehicle by as much as 50 percent, thereby reducing the need for air-conditioning systems.

Many techniques for depositing metal and dielectric coatings onto glass are well-known. Examples of conventional deposition techniques include liquid or powder spray pyrolysis, wherein liquids or solid particles containing film forming reactants are sprayed onto the surface of a hot glass ribbon being produced by the well-known float glass process. A more convenient method for depositing coatings onto glass is by way of chemical vapor deposition, wherein vaporized film-forming precursors are reacted at or near the surface of a hot glass ribbon to form the metal or dielectric film thereon. Chemical vapor deposition does not suffer from the problems associated with either liquid or powder spray pyrolysis techniques. That is, the liquid spray pyrolysis technique substantially cools the hot glass ribbon, while the powder spray pyrolysis technique requires a complex, delicate powder handling and delivery system.

A process for providing fluorine-doped tungsten oxide on the surface of a substrate, which process comprises reacting together a tungsten alkoxide, an oxygen-containing compound, and a fluorine-containing compound at the surface of the substrate at a temperature and for a time sufficient to form a film of fluorine-doped tungsten oxide on the substrate.

• < Prev
• Next >