Surface Enhanced Raman Scattering (SERS) Effect and Applications

1
Mini Symposium on Surface Plasmons
Surface Enhanced Raman Scattering (SERS) Effect
and Applications
Cheng Guo 07/15/2008
2
1. Introduction to Surface enhanced Raman
scattering (SERS)
1920s discovery of Raman effect
1970s discovery of SERS effect of pyridine on
silver electrode surfaces
J. Am. Chem. Soc. 1977,99,5215
3
2. Theoretical explanations for SERS

• Electromagnetic field enhancement mechanism
• excitation of surface plasmon
• tends 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

• Chemical enhancement
• due to specific interactions, forming
  charge-transfer complexes
• the magnitude of chemical enhancement 10-100
  times

4
    3. SERS applications
trace analysis approaching single molecule
detection limit e.g. 100 pyridine molecules on Ag
electrode
classical electrochemical studies e.g. corrosion
processes, film growth, self-assembled monolayers
Efficient enhancing substrates Ag, Au and Cu,
rough surfaces or colloidal particles with the
size of tens of nanometers
surface enhanced anti-stokes Raman
scattering surface enhanced resonance Raman
scattering (SERRS)
biological samples e.g. DNA/protein detection
5
4. SERS related to our research
Example 1 C60 SERS signals
Vibrational spectroscopy, 2007, 43, 415
6
(c)
(b)
(a)
How about use H2_at_C60 in this system?
7
Example 2 multiplex SERS signals for DNA
detection
Science 2002, 297, 1536
8
Multiplex SERS application four-color DNA
sequencing by synthesis
PNAS, 2008, 105, 9145
9
Example 3 SERS single nanoparticle imaging
J.Phys.Chem. B, 2002, Vol. 106, 311
10
Detection of azido-dNTP for DNA sequencing
NNN asymmetric stretching at 2088 cm-1
Biospectroscopy 1998, 2, 233
11
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