Effect of annealing on the structural, optical, electrical and photocatalytic activity of ZrO_2-TiO_2 nanocomposite thin films prepared by sol-gel dip coating technique

摘要

Abstract ZrO2–TiO2 nanocomposite thin films were deposited onto quartz substrate by sol–gel dip coating technique. The structural, morphological, optical, electrical and photocatalytic properties of the films were studied for different annealing temperatures (500, 800 and 1200 °C). X-ray diffraction pattern of films annealed at 500 °C showed amorphous nature. Increase in crystallinity was observed in the films annealed at higher temperature. Films annealed at higher temperature showed the formation of orthorhombic ZrTiO4 phase. Field emission scanning electron microscopy (FESEM) revealed crack free surface and surface roughness was found to increase with increase in annealing temperature. Energy dispersive X-ray analysis confirmed the presence of Zr, Ti and O in these films. Band gap of the films decreased from 3.93 to 3.50 eV with increase in annealing temperature. Photoluminescence spectra of the films exhibited emission peaks in both UV and visible region of the electromagnetic spectra. The conductivity of the films increased with increase in annealing temperature. Photocatalytic activity of these films evaluated by monitoring the degradation of methylene blue solution increased with increase in annealing temperature.