Structure and antibacterial properties of Ag and N doped titanium dioxide coatings containing Ti2.85O4N phase, prepared by magnetron sputtering and annealing

Abstract

Study reports on structure and antibacterial properties of the Ag and N doped TiO2 coatings. The coatings were deposited on glass by direct current reactive magnetron sputtering. A titanium target with silver pins was sputtered in an Ar/O2/N2 atmosphere. The reactive gases flow ratio was varied. The TiO2:Ag,N coatings were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission and scanning electron microscopy (TEM, SEM), atomic force microscopy (AFM). The microbiological tests (S. aureus) of the coatings were also shown. The coatings consisting of crystalline Ag nanoparticles in an amorphous matrix were then annealed (500 °C/1 h) for crystallization. After the heat treatment, the coatings consisted of the Ti2.85O4N, anatase, rutile and silver phases. The crystallites of the formed phases were sized below 20 nm. This mixture of phases provided improved antibacterial properties activated by visible light.