Synthesis and properties of Au–Fe3O4 heterostructured nanoparticles

3.5–9nm Au–Fe3O4 hetero-dimers synthesized with 0.6M HDD and 2mmol Fe(CO)5. The dark domain represented Au nanoparticle, while the low contrast part belonged to Fe3O4 nanoparticle. [Display omitted] ► Au–Fe3O4 hetero-dimers were synthesized via a hot injection method. ► The hetero-dimers showed plasmon absorption and magnetization dual functionalities. ► Star-like Au–Fe3O4 nanocomposites were developed from the hetero-dimers. Au–Fe3O4 composite nanoparticles have received much research interest due to their promising biomedical applications. In this work, Au–Fe3O4 composites with well-defined dimer-like nanostructure were synthesized via thermal decomposition route. The surfactant 1,2-hexandicandiol has proved to be critical for the formation of the Au–Fe3O4 hetero-dimers. The hetero-dimers production yield could be significantly improved to be 90% when the 1,2-hexandicandiol concentration was optimized at 0.6M. The obtained Au–Fe3O4 hetero-dimers possess dual-functionalities of plasmon resonance and magnetization. Moreover, the Fe3O4 domain of the hetero-dimers can be tuned readily by adjusting the molar ratio between Fe and Au sources. Furthermore, it was demonstrated that these Au–Fe3O4 hetero-dimers could be further developed into star-like Au–Fe3O4 nanoparticles which showed plasmon absorption at NIR region.