Tracking Nanoelectrochemistry Using Individual Plasmonic Nanocavities.

Area of Science:

• Plasmonics and Nanotechnology
• Electrochemistry
• Spectroscopy

Background:

• Individual plasmonic nanoparticles on a mirror serve as electrodes in an electrochemical cell.
• An ultrathin molecular spacer separates gold nanoparticles from a bulk gold film.
• The plasmonic hotspot reveals local charge modification and molecular spacer polarizability.

Purpose of the Study:

• To study the optical response of individual plasmonic nanoparticles in real time under applied voltage.
• To utilize isolated plasmonic junctions for tracking nanoelectrochemistry dynamics.
• To investigate charge transfer and molecular polarizability changes at the nanoscale.

Main Methods:

• Utilizing gold nanoparticles as electrodes in an electrochemical cell.
• Employing dark-field and Raman spectroscopy on individual nanoparticles.
• Applying voltage to induce electrochemical changes and observing optical responses.

Main Results:

• Real-time monitoring of optical response and plasmonic hotspots.
• Observation of modified charge on the gold surface and changes in molecular spacer polarizability.
• Demonstrated electron shifting within gap molecules, evidenced by Raman emission enhancements and blue-shifts at negative potentials.

Conclusions:

• Isolated plasmonic junctions are effective for tracking nanoelectrochemistry dynamics.
• Optical properties of plasmonic nanoparticles provide insights into nanoscale electrochemical processes.
• Electron transfer within molecular spacers can be precisely controlled and observed.