Engineering Gold Nanoparticles in Compass Shape with Broadly Tunable Plasmon Resonances and High-Performance SERS

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Controlling nanoparticle morphology is crucial for tailoring optical and electronic properties.
• Seed-mediated growth is a versatile method for synthesizing anisotropic nanostructures.

Purpose of the Study:

• To synthesize a novel gold nanostructure with a unique compass shape.
• To investigate the role of surfactants in controlling nanoparticle morphology.
• To explore the plasmonic properties and potential applications of the synthesized nanostructures.

Main Methods:

• Seed-mediated growth approach using gold (Au) seeds.
• Employing a binary mixture of cetyltrimethylammonium bromide (CTAB) and sodium oleate (NaOL) as structure-directing agents.
• Characterization of nanostructure formation and optical properties.

Main Results:

• Achieved uniform and high-yield synthesis of gold (Au) compass-shaped nanoparticles.
• Demonstrated that a binary surfactant mixture (CTAB/NaOL) favors compass shape formation over single surfactant (CTAB).
• Observed two distinct plasmonic resonances due to anisotropic structure, with tunable longitudinal surface plasmon resonances from 600 to 865 nm.
• Reported self-assembly into 2D monolayers, creating hot spots for enhanced Raman scattering.

Conclusions:

• The binary surfactant system effectively directs the synthesis of anisotropic gold compass nanostructures.
• The tunable plasmonic properties make these nanostructures promising for optical applications.
• The self-assembled monolayers offer potential for high-performance surface-enhanced Raman scattering (SERS) applications.