Synthesis of highly branched gold nanodendrites with a narrow size distribution and tunable NIR and SERS using a multiamine surfactant.

Gold nanodendrites with a long and densely branched morphology were fabricated by a seed-mediated method in a solution containing gold nanoparticles (AuNPs), bis(amidoethyl-carbamoylethyl)octadecylamine (C18N3), HAuCl4, and the reducing agent ascorbic acid (AA). The length and density of the branches could be mediated by changing the AuNP seed and AA concentrations. The amphiphilic C18N3 molecules function as a template and induce the unique morphology of the AuNPs/C18N3 structures. The localized surface plasmon resonance (LSPR) peaks of the gold nanodendrites can be modulated from the visible (∼530 nm) to the near-infrared region (∼1100 nm) of the electromagnetic spectrum. Surface-enhanced Raman scattering (SERS) signals using rhodamine can also be mediated by changing the seed and AA concentrations. These unique highly branched gold nanodendrites with a narrow size distribution and tunable NIR and SERS spectra should have great potential in sensing applications.