Effects of Different Dispersion Methods on the Microscopical Morphology of 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 powderin 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 meehanism leading to different features of the surface morphologies for the TiO2 films is discussed.