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Title
Japanese: 
English:Quantitative Study of the Gold-Enhanced Fluorescence of CdSe/ZnS Nanocrystals as a Function of Distance Using an AFM Probe 
Author
Japanese: 李 尚潤, 中谷 耕太, 林 智広, 原 正彦.  
English: Sang Yun Lee, Kouta Nakaya, Tomohiro Hayashi, Masahiko Hara.  
Language English 
Journal/Book name
Japanese: 
English:Physical Chemistry Chemical Physics 
Volume, Number, Page Vol. 11    No. 21    Page 4403-4409
Published date Mar. 2009 
Publisher
Japanese: 
English:Royal Society of Chemistry 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
English: 
Official URL http://www.rsc.org/Publishing/Journals/CP/article.asp?doi=b819903e
 
DOI https://doi.org/10.1039/b819903e
Abstract We report total internal reflection fluorescence microscopy (TIRFM) measurements using an atomic force microscope (AFM) probe to investigate the quantitative fluorescence profiles of CdSe/ZnS nanocrystals (NCs), which interact with gold surfaces, as a function of the gold–NC distance. First, a silica bead was glued to an AFM cantilever. CdSe/ZnS NCs were then immobilized on the silica-bead-functionalized AFM probe for control of the gold–NC distance, while a gold thin film served as the metal surface on a glass substrate. As a result of coexistent fluorescence resonance energy transfer and localized surface plasmon resonance (LSPR) coupling, a strong enhancement was observed at 15 nm, while fluorescence suppression was seen at a proximal distance. For further quantitative discussions of the effects of the metal surface on the fluorescence behavior of single NCs, we introduced a gold-deposited silica bead onto the AFM cantilever to regulate the gold–NC distance. Subsequently, the CdSe/ZnS NCs were immobilized on a glass surface. As a result of compensation for the contribution of photobrightening, the NC fluorescence profile for the glass surface also clearly displayed the LSPR-coupled enhancement at 10 nm. In contrast, it was discovered that positioning of the gold surface at a proximal single NC gave rise to quenching of the NC fluorescence. Our findings suggest that a method using an NC-functionalized AFM probe allows us to quantitatively investigate the NC fluorescence under the effects not only of a metal surface but also of an evanescence field.

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