SERS detection of 4-Aminobenzenethiol based on triangular Au-AuAg hierarchical-multishell nanostructure

Area of Science:

• Nanotechnology
• Surface Chemistry
• Spectroscopy

Background:

• Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique.
• Developing efficient nanostructures is crucial for enhancing SERS sensitivity.
• 4-Aminobenzenethiol (4-ABT) is a common analyte for SERS studies.

Purpose of the Study:

• To investigate the surface-enhanced Raman signals of 4-Aminobenzenethiol (4-ABT) adsorbed on triangular Au-AuAg hierarchical-multishell nanostructures.
• To explore a simplified method for preparing Au-AuAg nanostructures for SERS applications.
• To correlate Raman intensity with the intermediate gap and dipole plasmon hybridization.

Main Methods:

• Synthesis of core-cavity-shell sandwich nanostructures (Au-AuAg) via galvanic replacement reaction between silver and chloroauric acid.
• Direct mixing of 4-Aminobenzenethiol (4-ABT) with gold nanoparticles on glass slides.
• Analysis of surface-enhanced Raman scattering (SERS) spectra, focusing on the b2 mode around 1140 cm⁻¹.

Main Results:

• A significant increase in SERS intensity for the b2 mode of 4-ABT was observed.
• The Au-AuAg substrate enhanced the signal intensity approximately 3.8 × 10² times compared to 4-ABT alone.
• A detection limit as low as 0.1 μM for 4-ABT in solution was achieved.
• Raman intensity showed a positive correlation with the intermediate gap, linked to dipole plasmon hybridization.

Conclusions:

• The developed Au-AuAg hierarchical-multishell nanostructures are effective SERS substrates.
• The simplified preparation method avoids complex multi-layer structures.
• The nanostructures enable sensitive and indirect quantification of 4-ABT concentration.