1. Surface Enhanced Raman Scattering (SERS) Effect and Applications Cheng Guo 07/15/2008 Mini Symposium on Surface Plasmons

2. 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

3. 2. Theoretical explanations for SERS A.Electromagnetic field enhancement mechanism excitation of surface plasmon tends to form spacially localized “hot areas” the magnitude of enhancement ~10 6 - 10 7 times for single colloidal silver, and ~10 8 for the gap between two coupled particles B.Chemical enhancement due to specific interactions, forming charge-transfer complexes the magnitude of chemical enhancement ~10-100 times

4. 3. SERS applications Efficient enhancing substrates: Ag, Au and Cu, rough surfaces or colloidal particles with the size of tens of nanometers classical electrochemical studies e.g. corrosion processes, film growth, self-assembled monolayers surface enhanced anti-stokes Raman scattering surface enhanced resonance Raman scattering (SERRS) biological samples e.g. DNA/protein detection trace analysis approaching single molecule detection limit e.g. 100 pyridine molecules on Ag electrode

5. 4. SERS related to our research Vibrational spectroscopy, 2007, 43, 415 Example 1: C60 SERS signals

6. How about use H 2 @C60 in this system? (a) (b) (c)

7. Example 2: multiplex SERS signals for DNA detection Science 2002, 297, 1536

8. PNAS, 2008, 105, 9145 Multiplex SERS application: four-color DNA sequencing by synthesis

9. J.Phys.Chem. B, 2002, Vol. 106, 311 Example 3: SERS single nanoparticle imaging

10. Detection of azido-dNTP for DNA sequencing N=N=N 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