The growth of a c-axis highly oriented sandwiched TiO2 film with superhydrophilic properties without UV irradiation on SnO:F substrate

A c-axis highly oriented sandwiched film composed of single-crystalline rutile TiO2 on SnO:F (FTO) substrate was fabricated by a simple hydrothermal technique. The sandwich structure of the TiO2 film was found to be constructed by two layers of TiO2 nanorods, which grew towards both directions of the bulk solution and the substrate, respectively. One TiO2 nanoparticle interlayer between them acted as the 'seed' layer. The length and the density of the TiO2 nanoarrays could be tuned by varying the experimental parameters such as temperature and time. The resultant TiO2 films showed a specific superhydrophilicity without any prior UV irradiation, which can be kept for a long period of time.