Effect of Visible and UV Illumination on the Water Contact Angle of TiO2 Thin Films with Incorporated Nitrogen

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• 作者：A. Borr&aacute ; s ; C. Ló ; pez ; V. Rico ; F. Gracia ; A. R. Gonz&aacute ; lez-Elipe ; E. Richter ; G. Battiston ; R. Gerbasi ; N. McSporran ; G. Sauthier ; E. Gyö ; rgy ; A. Figueras
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：February 1, 2007
• 年：2007
• 卷：111
• 期：4
• 页码：1801 - 1808
• 全文大小：224K
• 年卷期：v.111,no.4(February 1, 2007)
• ISSN：1932-7455

文摘

Doping TiO₂ with nitrogen is recognized as a procedure to get sensitization of this material with visible light.In the present work, incorporation of nitrogen within the structure of TiO₂ thin films has been accomplishedby N₂⁺ ion implantation in TiO₂ anatase thin films (50 keV ion energy for doses of 3 × 10¹⁶, 6 × 10¹⁶, and1.2 × 10¹⁷ ions cm^-2) and during preparation by metalorganic chemical vapor deposition (MOCVD) usingnitrogen as carrier gas. The analysis of the samples by X-ray photoemission spectroscopy (XPS) and for theMOCVD samples also by secondary ion mass spectroscopy (SIMS) has shown that nitrogen, in the form ofnitride-like species, (N/Ti ratios of 0.03 and 0.12 for the MOCVD and the implanted samples, respectively)has become effectively incorporated within the structure of TiO₂. The water contact angle on the implantedthin films varied from about 80ges/entities/deg.gif"> to around 30ges/entities/deg.gif"> when illuminated with visible light, depending on the iondose. Similarly, the MOCVD samples showed a sharp decrease in wetting contact angle under visible lightfrom about 80ges/entities/deg.gif"> to 55ges/entities/deg.gif">. In the two cases, the thin films reach total hydrophilicity by posterior UV irradiation.To account for these results, the possible existence of specific excitation mechanisms for visible or UV photons,the former involving the incorporated nitrogen atoms, is discussed.