Controlled synthesis of Au–Fe heterodimer nanoparticles and their conversion into Au–Fe3O4 heterostructured nanoparticles

Abstract

We report a facile synthesis of Au–Fe heterodimer nanoparticles (NPs) with tunable Au/Fe sizes and their sequential oxidations to Au–Fe₃O₄ heterostructured NPs with controllable morphologies. The size of Au in Au–Fe heterodimer NPs was tuned to be 4, 7 and 10 nm, while the Fe crystal structure was maintained as single-crystal bcc. Further oxidation of the as-synthesized Au–Fe NPs led to the formation of Au–hollow Fe₃O₄ yolk–shell, Au–hollow Fe₃O₄ heterodimer NPs and Au–porous hollow Fe₃O₄ yolk–shell NPs, depending on the size of the Au–Fe NPs and the oxidation conditions used. Our study has provided not only a variety of bifunctional NPs with tunable surface plasmon absorption and magnetic properties, but also a new general approach to design and synthesize multicomponent NPs with multiple heterostructures.