A Versatile AuNP Synthetic Platform for Decoupled Control of Size and Surface Composition

Area of Science:

• Nanotechnology
• Materials Science
• Chemical Synthesis

Background:

• Existing methods for synthesizing sub-10-nm gold nanoparticles (AuNPs) offer limited independent control over particle size and surface composition.
• This lack of control hinders systematic structure-function relationship studies and optimization of AuNP design parameters.

Purpose of the Study:

• To develop a modular, two-step synthesis strategy for precisely controlling gold nanoparticle size and surface functionality.
• To enable systematic investigations into AuNP structure-property relationships and facilitate the preparation of AuNPs with tailored characteristics.

Main Methods:

• Synthesized oleylamine (OAm)-capped gold nanoparticles (AuNPs) with sizes ranging from 2-7 nm by adjusting reaction temperature.
• Performed a subsequent thiol-for-OAm ligand exchange to introduce specific thiol ligands and mixed ligand compositions.
• Demonstrated compatibility with a wide array of thiol ligands for controlled surface functionalization and tunable solubility.

Main Results:

• Achieved fine-tuning of AuNP core size (2-7 nm) through temperature-controlled synthesis in oleylamine.
• Successfully generated thiol-capped AuNPs with desired surface functionalities via ligand exchange.
• Demonstrated precise control over mixed ligand composition and solubility across diverse solvents (water to hexane).

Conclusions:

• The reported two-step approach provides decoupled control over gold nanoparticle core size and ligand shell properties.
• This method offers a versatile toolbox for systematic screening of design parameters and facile preparation of AuNPs with specific target properties.