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Innovative Ti1–xNbxN–Ag Films Inducing Bacterial Disinfection by Visible Light/Thermal Treatment

Rtimi, Sami, Kiwi, John, Karimi, Ayat, Sanjinés, Rosendo
ACS applied materials & interfaces 2018 v.10 no.14 pp. 12021-12030
X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, autoclaving, disinfection, films (materials), irradiation, models, pH, scanning electron microscopy, silver, titanium dioxide
This study presents innovative Ti₁–ₓNbₓN–Ag films obtained by a suitable combination of low-energy and high-energy sputtering leading to bacterial inactivation. The bacterial inactivation kinetics by the TiNbN layers was drastically enhanced by the addition of 6–7% Ag and proceeded to completion within 3 h after the film autoclaving. By X-ray photoelectron spectroscopy (XPS), the samples after autoclaving presented in their upper layers TiO₂, Nb₂O₅ and Ag₂O with a surface composition of Ti₀.₈₁Nb₀.₁₉N₀.₉₉Ag₀.₀₆₈. Surface potential/pH changes in the Ti₁–ₓNbₓN–Ag films were monitored during bacterial inactivation. Surface redox processes during the bacterial inactivation were detected by XPS. The diffusion of Ag in the Ti₁–ₓNbₓN–Ag films was followed at 50 and 70 °C pointing. The beneficial thermal treatment points out to the bifunctional bacterial inactivation properties of these films and their potential application in healthcare facilities. Interfacial charge transfer (IFCT) under light irradiation between Ag₂O, Nb₂O₅ and TiO₂ is suggested consistent with the data found during the course of this study. The TiO₂/Nb₂O₅ lattice mechanism is discussed in the framework of the Verwey’s controlled valence model. The surface properties of the Ti₁–ₓNbₓN–Ag films were investigated by X-ray diffraction, atomic force microscopy, and scanning electron microscopy.