Fabrication and characterization of SERS-active silver clusters on glassy carbon

Yuling Wang, Hongjun Chen, Shaojun Dong*, Erkang Wang

*Corresponding author for this work

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

In this article, a novel technique for the fabrication of surface enhanced Raman scattering (SERS) active silver clusters on glassy carbon (GC) has been proposed. It was found that silver clusters could be formed on a layer of positively charged poly(diallyldimethylammonium) (PDDA) anchored to a carbon surface by 4-aminobenzoic acid when a drop containing silver nanoparticles was deposited on it. The characteristics of the obtained silver clusters have been investigated by atomic force microscopy (AFM), SERS and an SERS-based Raman mapping technique in the form of line scanning. The AFM image shows that the silver clusters consist of several silver nanoparticles and the size of the clusters is in the range 80-100 nm. The SERS spectra of different concentrations of rhodamine 6G (R6G) on the silver clusters were obtained and compared with those from a silver colloid. The apparent enhancement factor (AEF) was estimated to be as large as 3.1 × 104 relative to silver colloid, which might have resulted from the presence of 'hot-spots' at the silver clusters, providing a highly localized electromagnetic field for the large enhancement of the SERS spectra of R6G. The minimum electromagnetic enhancement factor (EEF) is estimated to be 5.4 × 107 by comparison with the SERS spectra of R6G on the silver clusters and on the bare GC surface. SERS-based Raman mapping technique in the form of line scanning further illustrates the good SERS activity and reproducibility on the silver clusters. Finally, 4-mercaptopyridine (4-Mpy) was chosen as an analyte and the lowest detected concentration was investigated by the SERS-active silver clusters. A concentration of 1.6 × 10-10 M 4-Mpy could be detected with the SERS-active silver clusters, showing the great potential of the technique in practical applications of microanalysis with high sensitivity.

Original languageEnglish
Pages (from-to)515-521
Number of pages7
JournalJournal of Raman Spectroscopy
Volume38
Issue number5
DOIs
Publication statusPublished - May 2007
Externally publishedYes

Keywords

  • 4-mercaptopyridine
  • Glassy carbon
  • R6G
  • SERS
  • Silver clusters

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