Molecular Coverage Modulates Chiral Surface-Enhanced Raman Scattering on Chiral Plasmonic Nanoparticles

Area of Science:

• Plasmonics
• Spectroscopy
• Nanotechnology

Background:

• Chiral surface-enhanced Raman scattering (SERS) using plasmonic substrates offers sensitive enantiomer recognition.
• Understanding molecular states like packing density and configuration is crucial for chiral SERS.
• Previous studies have largely overlooked the influence of these molecular states on chiral SERS.

Purpose of the Study:

• To investigate the impact of molecular states, specifically surface packing density and configurations, on chiral SERS signals.
• To explore the use of gold helical nanocubes as chiral plasmonic substrates for enhanced chiral SERS.
• To demonstrate a method for ultrasensitive enantiomer detection using molecular spacers.

Main Methods:

• Fabrication of gold helical nanocubes as chiral plasmonic substrates.
• Systematic variation of enantiomer concentration and structure to control molecular coverage.
• Utilizing chiral SERS to analyze the influence of molecular states on spectral signals.
• Employing achiral molecules as internal spacers for enhanced enantiomer detection.

Main Results:

• Chiral SERS signals were found to be highly sensitive to the molecular coverage of enantiomers.
• The packing density and configuration of surface-adsorbed enantiomers significantly affect chiral SERS.
• Achiral molecules were successfully used as spacers to achieve ultrasensitive enantiomer detection.

Conclusions:

• Molecular states, including packing density and configuration, are critical factors influencing chiral SERS.
• Gold helical nanocubes provide tunable optical properties for effective chiral SERS applications.
• The developed approach using molecular spacers offers a promising route for sensitive molecular chirality detection via Raman spectroscopy.