jp0639086_si_001.pdf (2.88 MB)
Growth of Gold Nanorods and Bipyramids Using CTEAB Surfactant
journal contribution
posted on 2006-08-24, 00:00 authored by Xiaoshan Kou, Shuzhuo Zhang, Chia-Kuang Tsung, Man Hau Yeung, Qihui Shi, Galen D. Stucky, Lingdong Sun, Jianfang Wang, Chunhua YanGold nanorods and bipyramids have been synthesized using the seed-mediated approach in aqueous
cetyltriethylammonium bromide (CTEAB) solutions in the presence of silver nitrate. Gold nanoparticle seeds
that are stabilized with either CTEAB or sodium citrate have been used. The use of the CTEAB-stabilized
seeds gives gold nanorods in high yield in one step with the longitudinal plasmon wavelength ranging from
750 to 1030 nm, depending on the amount of the seeds. The longitudinal plasmon wavelength can be extended
to 1100 nm by the use of a two-step growth method. The growth of gold nanorods in CTEAB solutions takes
5−10 h, more than 5 times slower than that in cetyltrimethylammonium bromide solutions at the same
concentration of surfactants. The use of the citrate-stabilized seeds gives both gold bipyramids and a small
percentage of gold nanorods. The longitudinal plasmon wavelength of the bipyramids is tunable from 700 to
1100 nm by varying the amount of the citrate-stabilized seeds. The growth of gold bipyramids takes more
than 1 day. Transmission electron microscopy characterizations reveal that the gold nanorods grown from
both types of gold nanoparticle seeds are single-crystalline and that the gold bipyramids are penta-twinned.