Super-hydrophilic Ce3+-doped TiO2-SiO2 nanocomposite thin films with high optical transmittance by a simple spin-coating method

Super-hydrophilic surfaces with slight water contact angles have a wide range of applications, especially for protective layers. Herein, high-purity 10-layer TiO2-SiO2:x%Ce3+ (x = 0 – 8) nanocomposite thin films (NCTFs) were fabricated by a facile spin-coating method. The X-ray diffraction, the Fourier transform-infrared spectroscopy, and Raman spectroscopy results confirmed the formation of the TiO2-SiO2 NCTFs. X-ray photoelectron spectroscopy analysis strongly demonstrated the coexistence of Ce3+ and Ce4+ oxidation states on the surface of the NCTFs sample. The TiO2-SiO2:6%Ce3+ NCTFs exhibited the highest transmittance of 87.7% in the visible region and the lowest bandgap of 2.85 eV. Water contact angle results reveal that the NCTFs are super-hydrophilic under prolonged exposure to blue light (460 nm) irradiation. Our results demonstrate that the Ce3+-doped TiO2-SiO2 NCTFs are to be used as a photovoltaic material, protective film for glasses, and other surfaces.