Transparent self-cleaning coating applicable to solar energy consisting of nano-crystals of titanium dioxide in fluorine doped tin dioxide

• Coatings exhibit sunlight-activated hydrophilic self-cleaning characteristics.
• Self-cleaning coating on glass with high transparency (up to 89%) to visible light.
• Electrically conducting coating consisting of titanium dioxide nano particles embedded in fluorine doped tin dioxide.

A novel self-cleaning coating on soda-lime glass was obtained from a dispersion of titanium dioxide nanocrystals in an ethanolic solution of cis-di(ethyl formate) tetrachloride tin and ammonium bifluoride. Applying this suspension via spray pyrolysis to the glass substrate at 500 °C, resulted in the fluorine doped tin dioxide (FTO) coating with embedded titanium dioxide nano particles. The coating was thin enough so that the transmission of light through the coated glass is similar to uncoated glass in the visible region (350–800 nm). The FTO/titanium dioxide coated glass exhibits photocatalytic activity on exposure to ultraviolet light in a laboratory setting and when placed outdoors in natural sunlight. A preliminary field test was conducted where samples of uncoated glass and FTO/titanium dioxide coated glass where placed outdoor side-by-side for six months. Uncoated glass samples became soiled resulting in a decreased transparency to circa 74–67%T at 525 nm (90%T at 525 nm when clean). In contrast the coated glass samples decreased only slightly to circa 86%T at 580 nm (88%T at 525 nm when clean).

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