Single-Molecule Level Rare Events Revealed by Dynamic Surface-Enhanced Raman Spectroscopy

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Surface Science

Background:

• Surface-enhanced Raman spectroscopy (SERS) offers high-resolution molecular insights at interfaces.
• Challenges exist in SERS for analytes with weak binding affinity due to short surface dwell times.

Purpose of the Study:

• To investigate the adsorption/desorption behavior of R6G on Ag surfaces using dynamic SERS.
• To enhance SERS signal quality for mobile molecules and capture rare molecular events.

Main Methods:

• Employed dynamic SERS, a rapid acquisition method for consecutive SERS spectra.
• Studied the adsorption and desorption of R6G (Rhodamine 6G) on silver (Ag) surfaces.

Main Results:

• Dynamic SERS improved the signal-noise ratio for mobile molecules, even with diffusion limitations.
• Successfully captured the neutral R6G ⁰ state at the single-molecule level, distinct from the prevalent R6G ⁺ state.
• Demonstrated enhanced signal quality for analytes with weak binding affinities.

Conclusions:

• Dynamic SERS provides near real-time vibrational information with improved signal-noise ratio.
• This method enables the detection of metastable or rare molecular events.
• Opens new possibilities for understanding interfacial processes in catalysis and life science.