Synthesis and growth mechanism of long ultrafine gold nanowires with uniform diameter

Homogeneous Au nanowires with 1.5 nm diameters and lengths of over 100 μm were synthesized in an oleylamine matrix via the simple reduction of aurichloride in a limited reaction temperature range around 85 °C. Oleylamine has multifunctional roles as solvent, surfactant, and reductant, and the surfactant induce anisotropic growth by adsorbing on the specific Au crystalline surface. As a result, Au nanowires were grown along the ⟨111⟩ direction of fcc-Au having many hcp atomic stacks. In this synthesis method, various shapes of Au nanostructures were produced simultaneously and this was strongly dependent on the reaction temperature. Au nanowires were provided by reconstruction from nanoparticles or their agglomeration. The growth mechanism of the Au nanowire in this synthesis was found to be quite unique and different from that for a conventional one-dimensional nanostructure which is obtained by anisotropical growth with supplying atoms from external resources.