Plasmonic response and SERS modulation in electrochemical applied potentials

Area of Science:

• Nanophotonics and Plasmonics
• Electrochemistry
• Surface-Enhanced Raman Spectroscopy (SERS)

Background:

• Plasmonic nanocavities offer unique optical properties for sensing.
• Electrochemical control provides a dynamic way to tune nanostructure behavior.
• Surface-Enhanced Raman Spectroscopy (SERS) enables highly sensitive molecular detection.

Purpose of the Study:

• To investigate the optical response of plasmonic nanocavities acting as electrodes.
• To explore voltage-induced modulation of plasmonic spectra and SERS signals.
• To understand the electronic interactions between nanoparticles and electrode surfaces.

Main Methods:

• Utilized a nanoparticle-on-mirror (NPoM) design as an electrochemical cell electrode.
• Employed gold (Au) nanoparticles separated from a bulk Au film by a molecular spacer.
• Applied voltage in various electrolytes to modulate optical and SERS responses.

Main Results:

• Achieved intense and stable SERS amplification for approximately 100 molecules.
• Observed significant modulation of plasmonic spectra with applied voltage.
• Demonstrated voltage-dependent changes in SERS response.

Conclusions:

• The NPoM design functions effectively as an electrochemically tunable plasmonic sensor.
• Applied voltage influences the electronic interactions at the nanoparticle-electrode interface.
• This work provides insights into mechanisms for electrochemically controlled plasmonic and SERS phenomena.