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Distinguishable behavior of multiple and individual rhodamine‐6G molecules on spherical Ag nanoparticles examined via time dependence of the SERS spectra
Author(s) -
Luo Zhixun,
Hunter Woodward W.,
Castleman A. W.
Publication year - 2012
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4107
Subject(s) - rhodamine 6g , molecule , nanoparticle , surface enhanced raman spectroscopy , raman spectroscopy , substrate (aquarium) , spectral line , adsorption , laser ablation , materials science , desorption , spectroscopy , chemistry , chemical physics , nanotechnology , analytical chemistry (journal) , laser , raman scattering , optics , organic chemistry , physics , oceanography , quantum mechanics , astronomy , geology
We report a surface‐enhanced Raman spectroscopy (SERS) investigation to probe the adsorption and dynamic behavior of rhodamine 6 G (Rh6G) molecules on spherical Ag nanoparticles which were produced via laser ablation in liquid. Assembly of the colloidal Ag nanoparticles on a cover glass was used to work as SERS substrates on which high‐quality SERS spectra of Rh6G were obtained with interesting time dependence when using low and ultralow concentrations, respectively. The variation of SERS spectra over time was identified with the adsorption behavior of multiple and individual molecules on the Ag nanoparticles. Analysis indicates that the adsorbed Rh6G molecules can desorb away from the initial locations on the substrate under continuous laser excitation; simultaneously, some individual molecules can move and become trapped in the gap between the aggregated Ag nanoparticles. These investigations help to clarify the origins of forming ‘hot‐spots’ which host probe molecules and hence improve the understanding of mechanisms for single‐molecule SERS spectroscopy. Copyright © 2012 John Wiley & Sons, Ltd.