Monitoring the electrochemistry of single molecules by surface-enhanced Raman spectroscopy

EMILIANO CORTÉS, PABLO ETCHEGOIN, ERIC C. LE RU, ALEJANDRO FAINSTEIN, MARÍA E. VELA, ROBERTO C. SALVAREZZA

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2010 vol. 132 p. 18034 - 18037

0002-7863

ABSTRACT Coherent control of chemical species in complex systems is always subject to intrinsic inhomogeneities from the environment. For example, slight chemical modifications can decisively affect transport properties of molecules on surfaces. Hence, single molecule (SM) studies are the best solution to avoid these problems and to study diverse phenomena in biology, physics and chemistry. Along these lines, monitoring single molecule redox processes has always been a “holy grail" in electrochemistry. So far, claims of SM-electrochemistry by spectroscopy came only from polymer fluorescence quenching and redox-fluorescent molecules. In unconnected developments, the potential of the bi-analyte Surface-Enhanced Raman Scattering (SERS) method as a technique with SM-sensitivity has been demonstrated. Raman has the potential to explore SM detection of any molecule – independent of its chemical nature. We provide definitive proof of SM-events following redox cycles using SERS. The superior sensitivity and spectral richness of SERS makes it general enough to study, in principle, SM-electron transfer of any (label-free) molecule.