Facile synthesis of spherical nanoparticles with a silica shell and multiple Au nanodots as the core

Abstract

Highly spherical nanoparticles with a core comprising multiple gold (Au) nanodots and a silica shell (multi-Au@SiO₂ NPs) were successfully synthesized through a reverse (water-in-oil) microemulsion-based method. The microemulsion was prepared by mixing a surfactant (Brij35), cyclohexane, n-hexanol, and aqueous HAuCl₄ solution. Multiple Au nanodots with a maximum diameter of ∼5 nm could be encapsulated within a silica matrix during the growth process. The size of the multi-Au@SiO₂ NPs and the number of Au nanodots doped could be controlled by varying the water-to-Brij35 ratio and the amount of the precursor of cationic gold ions. This is a novel and simple synthetic approach for generating hybrid Au–silica nanomaterials by encapsulating multiple Au nanoparticles within a silica matrix.