posted on 2013-02-13, 00:00authored byXingchen Ye, Chen Zheng, Jun Chen, Yuzhi Gao, Christopher B. Murray
We report a dramatically improved synthesis of colloidal
gold nanorods
(NRs) using a binary surfactant mixture composed of hexadecyltrimethylammonium
bromide (CTAB) and sodium oleate (NaOL). Both thin (diameter <25
nm) and thicker (diameter >30 nm) gold NRs with exceptional monodispersity
and broadly tunable longitudinal surface plasmon resonance can be
synthesized using seeded growth at reduced CTAB concentrations (as
low as 0.037 M). The CTAB–NaOL binary surfactant mixture overcomes
the difficulty of growing uniform thick gold NRs often associated
with the single-component CTAB system and greatly expands the dimensions
of gold NRs that are accessible through a one-pot seeded growth process.
Gold NRs with large overall dimensions and thus high scattering/absorption
ratios are ideal for scattering-based applications such as biolabeling
as well as the enhancement of optical processes.