Growth of micro flower rutile TiO2 films by chemical bath deposition technique: Study on the properties of structural, surface morphological, vibrational, optical and compositional

In the present investigation, micro flower rutile TiO2 thin films have been prepared on glass substrate by chemical bath deposition technique for the first time without the use of any additives or surfactants. X-ray diffraction study confirmed the rutile phase and nanocrystalline nature of TiO2 films. Field emission scanning electron microscopic study revealed the titanium (IV) isopropoxide concentration induced change in morphology. These rutile TiO2 films possess a high surface area of 47 m2/g and pore size of 3.5 nm. Micro-Raman study revealed the presence of silent phonon mode at 113 cm−1 due to the phonon confinement effect (finite size effect). In addition, the rutile Raman active modes such as Eg (436 cm−1) and A1g (605 cm−1) and second order modes at 237 cm−1 and 691 cm−1 are observed in the present work. The compositional purity of the films was confirmed by X-ray photoelectron spectroscopy (XPS). The rutile TiO2 films excited at 350 nm showed the strong and intense UV emission at 3.49 eV which corresponding to exciton emission. The direct energy band gap value of the film varies from 3.08 to 3.07 eV as calculated by Kubelka-Munk method which was further confirmed by the valence band XPS spectrum.