The preparation of high-surface-area nanocrystalline TiO2 films using easy-reaggregation particles in solution

A high-surface-area nanocrystalline TiO2 films were successfully prepared from two kinds of easy-reaggregation primary nanoparticles with the mean size of 26 nm in ethanol solution by a novel technique of quickly volatilizing solvent to fix the nanoparticles. Structure and properties of the films were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that the mean size of nanoparticles does not change with heat-treatment at 450 °C and the roughness factor about 86 and 80 was obtained for 1 μm thickness films. A roughness factor of 82 was found for the commercial P25 TiO2 films with the mean size of 36 nm and the same thickness. The electrochemical properties of the bare interfaces of the TiO2 film electrodes in propylene carbonate (PC) containing 0.05 M tetrabutyl ammonium bromide (TBAB) was also measured and show that the electroactive of the TiO2(I) film is similar to P25. Moreover, this method is adapted to prepare nanostructural films using other materials and smaller primary nanoparticles for dye-sensitized nanocrystalline solar cells.