surface enhanced raman scattering (sers) effect and applications cheng guo 07/15/2008 mini symposium...
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Surface Enhanced Raman Scattering (SERS) Effect and Applications
Cheng Guo07/15/2008
Mini Symposium on Surface Plasmons
1. Introduction to Surface enhanced Raman scattering (SERS)
1920’s discovery of
Raman effect
1970’s discovery of SERS effect of pyridine on silver electrode surfaces
J. Am. Chem. Soc. 1977,99,5215
2. Theoretical explanations for SERS
A. Electromagnetic field enhancement mechanismexcitation of surface plasmontends to form spacially localized “hot areas”the magnitude of enhancement ~106- 107 times for single colloidal silver, and ~108 for the gap between two coupled particles
B. Chemical enhancement due to specific interactions, forming charge-transfer complexesthe magnitude of chemical enhancement ~10-100 times
3. SERS applications
Efficient enhancing substrates: Ag, Au and Cu, rough surfaces or colloidal particles with the size of tens of nanometers
classical electrochemical studiese.g. corrosion processes, film growth, self-assembled monolayers
surface enhanced anti-stokes Raman scatteringsurface enhanced resonance Raman scattering (SERRS)
biological samplese.g. DNA/protein detection
trace analysis approaching single molecule detection limite.g. 100 pyridine molecules on Ag electrode
Detection of azido-dNTP for DNA sequencing
N=N=N asymmetric stretching at 2088
cm-1
Biospectroscopy1998, 2, 233
Summary
1. Surface Enhanced Raman Scattering (SERS) has been discovered for many decades and the surface plasmon resonance theory helped explain the mechanism
2. SERS was applied in many research fields. Current study of SERS in C60, multiplex SERS for DNA detection and AZT-dNTP SERS signals are useful to our research