Hydrothermal synthesis of TiO2 nanostructures on pre-treated substrate

Properties of a substrate play a very important role in determining the properties of nanostructures formed onto its surface. Optimizing the parameters of sol-gel, TiO₂ nanostructures were synthesized on a pre-treated glass substrate by using hydrothermal method. Ten samples were prepared; each had a different thickness of TiO₂ layer prepared by spin coating technique. After annealing was done, five samples then were selected for immersion in TiO₂ solution. The crystalline structure of the films was studied by Raman spectroscopy. As the number of TiO₂ coating layer was increased, the result showed a transition from amorphous to anatase crystalline phase for non-immersed samples. With immersion, the presence of anatase crystalline phase was observed in all samples. The UV-visible spectrum showed no significant change among all the samples, with high absorbance in the UV region and transparent in the visible region. The surface morphology was checked by atomic force microscopy (AFM), which confirmed that the roughness increased after immersion; 0.410 to 8.715 for 1-layer coating, and 1.171 to 8.542 for 5-layer coating.