Synthesis and properties of Au–Fe₃O₄and Ag–Fe₃O₄heterodimeric nanoparticles

Abstract

Monodisperse Au–Fe3O4 heterodimeric nanoparticles (NPs) were prepared by injecting precursors into a hot reaction solution. The size of Au and Fe3O4 particles can be controlled by changing the injection temperature. UV–Vis spectra show that the surface plasma resonance band of Au–Fe3O4 heterodimeric NPs was evidently red-shifted compared with the resonance band of Au NPs of similar size. The as-prepared heterodimeric Au–Fe3O4 NPs exhibited superparamagnetic properties at room temperature. The Ag–Fe3O4 heterodimeric NPs were also prepared by this synthetic method simply using AgNO3 as precursor instead of HAuCl4. It is indicated that the reported method can be readily extended to the synthesis of other noble metal conjugated heterodimeric NPs.