Effects of Different Dispersion Methods on the Microscopical Morphologyof TiO₂ Film

Nanocrystalline porous TiO2 films were prepared on conducting glass supports (ITO) by processed commercial TiO₂ nanometre powder (P25). Three methods of physical dispersing for TiO₂ powder, i.e. grinding, magnetic stirring, sonicleaning, were used to disperse TiO₂ nanometre powder. Surface morphologies of TiO₂ films were observed by optic-microscope and SEM. It is
found that the surface morphologies of TiO₂ films are determined not only by the dispersing methods but also by the percentage of TiO₂ powder in the dispersing system. Different film morphologies can be obtained under the same preparation condition but with different dispersing methods. A lot of cracks exist on the film surface for which the TiO₂ slurry is dispersed by grinding. Magnetic stirring leads to some white points and micro-holes on the
film surface. Only a few of micro-holes can be observed on the film surface, in which the TiO₂ slurry is dispersed by sonicleaning. Different surface morphologies can also be found with different thicknesses of TiO2 films. Different film thicknesses are due to different percentages of TiO₂ powder in the slurry. The related mechanism leading to different features of the surface morphologies for the TiO₂ films is discussed.