Structural and Optical Investigation of Sol–Gel-Derived TiO2 Films Deposited on Transparent Substrates

In the present work, thin TiO2 films were obtained by the sol–gel spin-coating method on glass and ITO-covered glass substrates. The crystallization evolution of the thin films was studied by the X-ray Diffraction (XRD) technique. The results indicate that the films’ crystalline structure was greatly affected by substrate type. X-ray photoelectron spectroscopy (XPS) revealed the chemical states of the TiO2 films and proved the formation of TiO2 on ITO substrates. Field Emission Scanning Electron Microscopy (FESEM) showed that the TiO2 films deposited on the ITO glass possessed a uniform and homogeneous surface morphology. The influence of optical properties (transmittance, reflectance, and optical band gap) on substrate type, the number of layers and annealing temperatures was determined. Spectroscopic data confirmed high transparency of the TiO2 films obtained on ITO substrates as the transmittance in the visible spectral range was close to 85%. The obtained results reveal that thin TiO2 films on ITO substrates can be an excellent candidate for photovoltaic and optoelectronic applications.