Paper
18 June 2001 Observing single-molecule chemical reactions on metal nanoparticles
Steven R. Emory, W. Patrick Ambrose, Peter M. Goodwin, Richard A. Keller
Author Affiliations +
Abstract
We report on the study of the photodecomposition of single Rhodamine 6G (R6G) dye molecules adsorbed on silver nanoparticles. The nanoparticles were immobilized and spatially isolated on polylysine-derivatized glass coverslips, and confocal laser microspectroscopy was used to obtain surface-enhanced Raman scatters (SERS) spectra from individual R6G molecules. The photodecomposition of these molecules was observed with 150-ms temporal resolution. The photoproduct was identified as graphitic carbon based on the appearance of bread SERS vibrational bands at 1592 cm-1 and 1340 cm-1 observed in both bulk and averaged single-molecule photoproduct spectra. In contrast, when observed at the single-molecule level, the photoproduct yielded sharp SERS spectra. The inhomogeneous broadening of the bulk SERS spectra is due to a variety of photoproducts in different surface orientations and is a characteristic of ensemble-averaged measurement of disordered systems. These single-molecule studies indicate a photodecomposition pathway by which the R6G molecule desorbs from the metal surface, an excited-state photoreaction occurs, and the R6G photoproduct(s) readsorbs to the surface. A SERS spectrum is obtained when either the intact R6G or the R6G photoproduct(s) are adsorbed on a SERS-active site. This work further illustrates the power of single-molecule spectroscopy (SMS) to reveal unique behaviors of single molecules that are not discernable with bulk measurements.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Steven R. Emory, W. Patrick Ambrose, Peter M. Goodwin, and Richard A. Keller "Observing single-molecule chemical reactions on metal nanoparticles", Proc. SPIE 4258, Nanoparticles and Nanostructured Surfaces: Novel Reporters with Biological Applications, (18 June 2001); https://doi.org/10.1117/12.430762
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Cited by 5 scholarly publications.
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KEYWORDS
Molecules

Nanoparticles

Surface enhanced Raman spectroscopy

Silver

Carbon

Raman spectroscopy

Metals

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