Room-Temperature Molecular Manipulation via Plasmonic Trapping at Electrified Interfaces.

Area of Science:

• Nanotechnology
• Physical Chemistry
• Spectroscopy

Background:

• Optical tweezers offer high-resolution control of molecules but face challenges with small molecules at room temperature due to thermal fluctuations.
• Molecular polarizability variations and orientation dependence complicate optical manipulation.
• Controlling molecular behavior at interfaces is crucial for various chemical and physical processes.

Purpose of the Study:

• To demonstrate plasmonic optical trapping for manipulating small molecules (<1 nm) at room temperature.
• To investigate selective molecular condensation and phase formation using plasmonic structures.
• To establish a methodology for plasmonic optical trapping at electrified interfaces.

Main Methods:

• Utilized a single metal nanodimer immersed in an electrolyte solution for plasmonic optical trapping.
• Employed in situ electrochemical surface-enhanced Raman scattering (SE-SERS) measurements.
• Applied electrochemical potential control and optical forces to study molecular behavior.

Main Results:

• Achieved plasmonic optical trapping of molecules smaller than 1 nm.
• Demonstrated selective molecular condensation and formation of unique mixed molecular phases distinct from thermodynamic equilibrium.
• Established a novel adsorption isotherm under applied optical force at electrified interfaces.

Conclusions:

• Plasmonic optical trapping is a viable method for controlling small molecules at room temperature.
• Electrochemical control of plasmonic structures enables precise manipulation and formation of non-equilibrium molecular phases.
• This methodology opens new avenues for studying and controlling molecular adsorption at electrified interfaces.