Multiple nano-TiO2 layers to prevent dye/nano-TiO2 from photodegradation under a UV-exposure environment

A device of multiple nano-TiO₂ layers was proposed and fabricated to prevent a dye/nano-TiO₂ region from serious photo-degradation. In this device, the top of the dye/TiO₂ region was designed to be coated using sol-gel nano-TiO₂ thin films to shield UV irradiation from the photo-degradation effect. The sol-gel TiO₂ was prepared in a low temperature (75 °C) and verified as nano-sized particles and an anatase crystalline structure. Different devices of the multi-layer samples fabricated using different compositions of nano-TiO₂ were produced and exposed for UV irradiation tests. Results show that the presence of the sol-gel TiO₂ films coated on top of the dye/TiO₂ region can significantly alleviate the dye photo-degradation under UV irradiation. This multi-layer device can effectively improve the photo-stability of the dye/TiO₂ region in a UV-exposure environment.