Two-Functional Direct Current Sputtered Silver-Containing Titanium Dioxide Thin Films

• Published in: Nanoscale research letters 2009-04, Vol.4 (4), p.313-320
• Main Authors: Musil, J, Louda, M, Cerstvy, R, Baroch, P, Ditta, I. B, Steele, A, Foster, H. A
• Format: Article
• Language: English
• Subjects: Ag addition; Biocidal activity; Hydrophilicity; Mechanical properties; Sputtering; TiO2
• ISSN: 1931-7573; 1556-276X; 1556-276X
• DOI: 10.1186/1556-276X-4-313

The article reports on structure, mechanical, optical, photocatalytic and biocidal properties of Ti-Ag-O films. The Ti-Ag-O films were reactively sputter-deposited from a composed Ti/Ag target at different partial pressures of oxygen [graphic removed] on unheated glass substrate held on floating potential U fl. It was found that addition of ~2 at.% of Ag into TiO₂ film has no negative influence on UV-induced hydrophilicity of TiO₂ film. Thick (~1,500 nm) TiO₂/Ag films containing (200) anatase phase exhibit the best hydrophilicity with water droplet contact angle (WDCA) lower than 10° after UV irradiation for 20 min. Thick (~1,500 nm) TiO₂/Ag films exhibited a better UV-induced hydrophilicity compared to that of thinner (~700 nm) TiO2/Ag films. Further it was found that hydrophilic TiO₂/Ag films exhibit a strong biocidal effect under both the visible light and the UV irradiation with 100% killing efficiency of Escherichia coli ATCC 10536 after UV irradiation for 20 min. Reported results show that single layer of TiO₂ with Ag distributed in its whole volume exhibits, after UV irradiation, simultaneously two functions: (1) excellent hydrophilicity with WDCA < 10° and (2) strong power to kill E. coli even under visible light due to direct toxicity of Ag.