Probe of ZrTiO2 thin films with TiO2-ZrO2 binary oxides deposited by dip coating technique

Zirconium Titanium dioxide (TiO2: Zr) thin films were synthesized on glass substrates by the dip coating technique. The structural, optical, magnetic, photo-catalytic and antibacterial properties were explored for the films synthesized with zirconium concentration 10, 15, 20, 25 and 30 at.%. X-ray diffraction (XRD) revealed that the thin films contain anatase-rutile-brookite TiO2 and cubic-ZrO2 phases. Moreover, it was noticed that ZrO2 retarded the anatase-to-rutile transformation at high Zr doping percentage.The crystallite size of ZrO2 phase was in the range of 10.93-18.22 nm, whereas it was in the range of 13.5-21.59 nm for TiO2 phase for same Zr doping percentage. The band gap of films was in the range of 2.99-3.17 eV. The band gap value decreased with increase in Zr-doping percentage due to the creation localized levels near the conduction band providing a large number of electrons to reach the conduction band. Films showed room temperature ferro-magnetism due to the defects produced by Zr in TiO2 lattice. The antibacterial efficiency of ZrTiO2 thin films was investigated by utilizing disc diffusion method. Band gap was quite low, then pure TiO2 in the range 2.99-3.14 eV with Zr percentage 10-30% atom. The ZrTiO2 thin films with 20 and 25% Zr showed better antibacterial activity against Escherichia coli than 10, 15 and 30% Zr. It was found that ZrTiO2 thin films were effective solar light photo-catalyst.