Single-molecule SERS detection of C60

Area of Science:

• Nanotechnology
• Spectroscopy
• Materials Science

Background:

• Surface-Enhanced Raman Scattering (SERS) is a powerful technique for detecting molecules at the single-molecule level.
• Buckminsterfullerene (C(60)) is a significant carbon allotrope with unique electronic and structural properties.

Purpose of the Study:

• To achieve single-molecule SERS detection of buckminsterfullerene (C(60)) using isotopically substituted molecules.
• To investigate the impact of isotopic disorder on SERS spectra at the single-molecule level.

Main Methods:

• Utilizing isotopologues of C(60) with approximately 30% (13)C substitution.
• Employing SERS with silver (Ag) metallic colloids to achieve high enhancement factors (~10^8).
• Analyzing the spectral features of individual isotopic realizations of C(60).

Main Results:

• Distinguishing single-molecule SERS spectra within a broadened average signal (~20 cm(-1)) due to isotopic distribution.
• Observed broader SERS peaks (FWHM ≈ 4 cm(-1)) for isotopically substituted C(60) compared to natural C(60).
• SERS enhancement factors for single-molecule C(60) events were around 10^8, potentially limited by photobleaching or surface interactions.

Conclusions:

• The study demonstrates the feasibility of single-molecule SERS detection for C(60) using isotopic mixtures.
• Isotopic disorder in C(60) contributes to homogeneous broadening in single-molecule SERS spectra.
• This technique provides a novel approach to probe molecular heterogeneity and isotopic effects.