Dipping Time and Annealing Effect on TiO2 Thin Films Grown by Sol-Gel Dip Coating Method (SGDC)

Abstract

TiO2 semiconductor is highly functional materials for solar cell applications such as photo catalysis and photovoltaics owing to the superior opto electrical properties and chemical stability. Annealing temperature and dipping time effect on TiO2 thin films grown by SG-DC method were investigated. The solution was prepared using Titanium (IV) Isopropoxide (TTIP), ethanol and acetone solutions are used. TiO2 thin films grown by Dip Coating method on glass substrates with 5, 10, 20 seconds dipping time at a speed of 0.5 cm/s and annealed at temperatures from 300°C to 600°C. Structural characterizations of TiO2 thin films were investigated by X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM), and optical properties were investigated by UV-Spectroscopy. According to XRD analysis, TiO2 anatase phase observed for unannealed and annealed at 300 0C thin films. The polycrystalline peaks observed after 400 0C and the peaks intensity, sharpness and narrowing are decreased with increasing temperature. From the absorption data, the band gap values (Eg) decreased from 3.31 to 3.06 eV with increasing annealing temperature and increase with increasing dipping time. The SEM analysis show that TiO2 nanoparticles grown spherical shape. It was determined that the dipping time and annealing temperature cause changing in the characteristic properties of TiO2 thin films.