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.