[Probing R6G single molecules by surface-enhanced resonance Raman scattering]

Area of Science:

• Spectroscopy
• Surface-enhanced resonance Raman scattering (SERRS)
• Single-molecule detection

Context:

• Investigating the surface-enhanced resonance Raman scattering (SERRS) of R6G dye molecules.
• Utilizing a confocal microscopy system for high-resolution spectral analysis.
• Employing silver colloids at low concentrations to study SERRS phenomena.

Purpose:

• To analyze the SERRS spectra of R6G at the single-molecule level.
• To characterize spectral inhomogeneities including diffusion, fluctuation, and blinking.
• To assess the influence of excitation light polarization and background subtraction on SERRS detection.

Summary:

• R6G dye was incubated in silver colloids, and its SERRS spectra were recorded at the single-molecule level (10(-13) mol x L(-1)).
• Observed phenomena included spectral diffusion, vibrational line intensity fluctuation, spectral polarization, and on/off blinking of spectral lines.
• The study analyzed the significant impact of excitation light polarization and background signal subtraction on single-molecule SERRS detection.

Impact:

• Provides insights into the complex behavior of molecules at the single-molecule level using SERRS.
• Highlights critical experimental parameters influencing the accurate detection and interpretation of SERRS spectra.
• Contributes to the understanding of plasmon-enhanced spectroscopy for sensitive molecular analysis.