Self-cleaning V-TiO2:SiO2 thin-film coatings with enhanced transmission for solar glass cover and related applications

We report the development of a self-cleaning transparent coating on glass prepared by spin coating V-TiO2:SiO2 mixed sol where visible light induced photocatalytic activity and superhydrophilicity aid to self-cleaning and antireflection (AR) property with low refractive index, as compared to uncoated substrate. To prepare V-TiO2-SiO2 coating V-doped TiO2 sol has been mixed with SiO2 sol by varying wt.% of V-TiO2, from 10% to 25%. The best optimized V-TiO2-SiO2 thin film composition i.e. 15 wt.% V-TiO2:SiO2 is found to exhibit >4% enhancement in the optical transmission of glass. Superhydrophilicity with water contact angle (WCA) similar to 5 degrees was also observed in case of 15 wt.% V-TiO2:SiO2. Upon O-2 plasma treatment we observe superhydrophilicity, with nearly 0 contact angle, for all the coating compositions. Further, V-TiO2:SiO2 coated glass substrate exhibits photocatalytic activity, in the presence of visible light, which is attributed to the V doping in TiO2 sol and demonstrated in the form of photodegradation of methylene blue dye. Simultaneous photocatalytic and self-cleaning property of the V-TiO2:SiO2 coating: aid in dissociation and removal of organic pollutants under visible light while at the same time are considered suitable for enhancing transparency required for architectural glass and PV module glass covers for high solar energy conversion efficiency. (C) 2017 Elsevier Ltd. All rights reserved.