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

Abstract

A high-surface-area nanocrystalline TiO 2 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 TiO 2 films with the mean size of 36 nm and the same thickness. The electrochemical properties of the bare interfaces of the TiO 2 film electrodes in propylene carbonate (PC) containing 0.05 M tetrabutyl ammonium bromide (TBAB) was also measured and show that the electroactive of the TiO 2 (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.