Influence of Film Thickness on Structural and Optical Properties of Sol – Gel Spin Coated TiO2 Thin Film

Abstract

Titanium dioxide thin films have been prepared from the solution of TTIP (Titanium Tetra Isopropoxide), Acetic acid and Ethanol on the glass substrates by sol-gel spin coating technique. In the present work, the TiO2 thin films have been analyzed for different coating cycles which were annealed at 450° C for one hour. The annealed films were characterized by X – Ray diffraction (XRD) method, UV – Visible & Photoluminescence (PL) spectroscopy, Field Effect Scanning Electron Microscopy (FESEM) and Energy Dispersive X – Ray Analysis (EDAX).The XRD results show that the crystallite size increases from 6.3 nm to 35.5 nm with increase in number of coating cycles. The transmittance of the film and the optical band gap are found to decrease with increase in number of coating cycles. The room temperature PL spectra of TiO2 thin films show blue and green emissions at 485 nm and 530 nm with excitation at 410 nm. The surface morphology shows rough surface with irregular particles. The stoichiometric ratio of the film was confirmed by EDAX analysis. The results of structural and optical characteristic study suggest that the sol-gel spin coated nanocrystalline TiO2 thin films can have high potential application in photo catalytic activities.