Optical Tracking of Single Ag Clusters in Nanostructured Water Films

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• 作者：Stefan Krause ; Martin Hartmann ; Ingolf Kahle ; Martin Neumann ; Mario Heidern盲tsch ; Stefan Spange ; Christian von Borczyskowski
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：November 27, 2013
• 年：2013
• 卷：117
• 期：47
• 页码：24822-24829
• 全文大小：413K
• 年卷期：v.117,no.47(November 27, 2013)
• ISSN：1932-7455

文摘

The spatial diffusion and size distribution of monodisperse silver nanoclusters synthesized via Ag(I) carboxylate in zeolite Y cages are investigated in nanostructured water films on silicon dioxide (SiO₂) and mica surfaces with optical and atomic force techniques. Subnanometer clusters escaping the zeolite Y cage show a strong and photostable fluorescence emission in the visible range and allow for optical single-cluster tracking. Heterogeneous diffusion dynamics reflect the transition from an ice-like to a liquid-like water film as a function of film thickness. The contributions of the different diffusion coefficients strongly correlate with the water film thickness and the chemical composition of the interface. The heterogeneity of the diffusion is caused by ad- and desorption of Ag clusters to silanol groups at the SiO₂ interface which couple vibronically to the Ag clusters as can be seen from single cluster fluorescence spectra.