Gold nanoparticle shape dependence of colloidal stability domains

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• Controlling nanoparticle arrangement is crucial for exploiting inter-particle plasmonic coupling and tuning optical properties.
• Bottom-up assembly of colloidal nanoparticles offers a route to complex structures.
• Cationic surfactants like CTAB are vital for synthesizing and stabilizing plasmonic gold nanoparticles (AuNPs).

Purpose of the Study:

• To understand and predict the colloidal stability of gold nanostructures in the presence of CTAB.
• To develop stability diagrams for colloidal gold nanostructures based on size, shape, and CTAB/AuNP concentration.
• To enable controlled self-assembly of gold nanoparticles into desired structures.

Main Methods:

• Generation of stability diagrams for colloidal gold nanostructures.
• Investigation of particle behavior using transmission electron microscopy.
• Systematic evaluation of stability across various nanoparticle shapes and concentrations.

Main Results:

• Colloidal stability is significantly influenced by nanoparticle shape, with sharp tips promoting instability.
• A metastable area was consistently observed, allowing controlled aggregation while maintaining colloidal stability.
• Linear gold nanostructures were successfully assembled with controlled particle numbers by utilizing the stability diagrams.

Conclusions:

• Shape plays a critical role in the colloidal stability of gold nanostructures with CTAB.
• Stability diagrams provide a predictive tool for controlling gold nanoparticle self-assembly.
• This work facilitates the creation of ordered nanostructures for plasmonic applications.