State Key Laboratory of Electroanalytical Chemistry,
Changchun Institute of Applied Chemistry,
Chinese Academy of Science,
Changchun 130022,
Jilin,
China
Raman imaging is a powerful analytical tool especially since the discovery of the SERS. Presently, there are two distinct Raman imaging concepts, first is the concept of global image based on the light distribution in a wild field and second, the image may be obtained by recording spectra point-by-point in the form of line scanning, analysis of areas of the sample, or analysis of volumes with the additional requirement of a confocal microscopy1. In addition to reports by McGlashen et al2 and by Evans et al3, Fujishima and co-workers are the first to describe the use of SERS as an image tool27. And later Acoca et al investigated the imaging and mapping of langmuir-blodgett monolayers based on SERS mapping4. So SERS-based Raman Mapping is a useful tool to investigate the morphology on the surface. In this study, we investigate the morphology of silver nanoparticles assembled on modified glassy carbon electrode (GCE) and on bare GCE by SERS-based Raman Mapping.
SERS spectra were obtained on the HORIBA Jobin Yvon
T64000 Raman spectrometer. And maps were recorded with
514.5
nm laser
line, using an Olympus microscope and a 50 microscopy
objective to focus the laser beam onto a spot of 1m2 and
mapping an area of 10 m 10 m on modified GCE and
70 m 70 m
on bare GCE. The sample was placed below the objective
lens on an XYZ stage equipped with a motion controller.
The sample surface was scanned sequentially in 1m steps
and the vibration at 1651 cm-1 of R6G was
obtained in 10s at each point.
Figure 1 gives the morphology of silver nanoparticles assembled on the modified GCE and on bare GCE. It can be seen clearly the distribution of silver nanoparticles assembled on modified GCE is relatively uniform while on bare GCE is not uniform because the Raman intensity of R6G on silver nanoparticles assembled on modified GCE distribute uniformly only some places higher which are the hot particles resided in, while on bare GCE, the intensity of R6G distribute very non-uniformly.
Figure 1: SERS-based Raman mapping of R6G at 1651cm-1 on silver nanoparticles assembled on modified GCE (a) and on bare GCE (b).
Acknowledgements
The work was supported by the National Nature Sciences Foundation
of China (NO.20275037, NO.20210506)
References
1. Aroca, R.F.; Constantino, C.J.L. Langmuir 2000, 16,5425-5429
2. McGlashen, M.L.; Guhathakurta, U.; Davis, K.L.; Morris,
M.D. Appl.Spectrosc. 1991, 45, 543
3. Evans, S.D.; Freeman, T.L.; Flynn, T.M.; Batchelder,D.N.
Thin Solid Films 1994, 244, 778-783
4. (a)Yang,X.M.; Ajito,K.; Tryk,D.A.; Hashimoto,K.; Fujishima,A.
J.Phys.Chem. 1996, 100,7293-7297. (b)Yang,X.M.; Tryk,D.A.;
Ajito,K.; Hashimoto,K.; Fujishima,A. Langmuir1996,12,5525-5527.
(c) Yang,X.M.; Tryk,D.A.; Ajito,K.; Hashimoto,K.; Fujishima,A.
J.Phys.Chem.1998,102,4933-4943
Contact
Weidong Wang for further information on +86 -431-5262420
E-mail: wwdong@ciac.jl.cn
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