(Invited) Recent Progress in the Study of Single Molecule Electrochemistry Using Surface-Enhanced and Tip-Enhanced Raman Spectroscopy

During the last few years, there has been an explosion of interest and activity in the field of plasmonics. The goal of plasmonics is to control and manipulate light on the nanometer length scale using the properties of the collective electronic excitations in noble metal films or nanoparticles, known as surface plasmons. An improved understanding of the interactions between adsorbed molecules and plasmonic nanostructures (i.e., molecular plasmonics) is having a significant impact in a number of research areas including electrochemistry, surface science, catalysis for energy conversion and storage, the materials science of nanoparticles, biomedical diagnostics, art conservation science, and nanolithography.

            In the first part of this lecture, I will provide some background material on the basic physical concepts underlying molecular plasmonics with an emphasis on surface-enhanced Raman spectroscopy (SERS), localized surface plasmon resonance (LSPR) spectroscopy, and tip-enhanced Raman spectroscopy (TERS).

            In the second part of this lecture, I will focus in on our most recent work in studying single molecule electrochemistry using surface-enhanced and tip-enhanced Raman spectroscopy. I will first describe the development of an instrument that has the capability of combining tip-enhanced Raman spectroscopy at the solid/liquid interface with scanning electrochemical microscopy (SECM). Next the single molecule Raman spectroelectrochemistry of Rhodamine 6G (R6G) at acetonitrile/Ag interface will be discussed. Finally, I will discuss the path forward toward the goal of understanding heterogeneous electron transfer at the single molecule level.