writer：Youju Huang, Liwei Dai, Liping Song, Lei Zhang, Yun Rong, Jiawei Zhang, Zhihong Nie*, Tao Chen*
keywords：Gold nanoparticles, plasmon resonances, surface-enhanced Raman scattering, seed-mediated growth
source：期刊
specific source：ACS Applied Materials & Interfaces, 2016, 8, 27949?27955
Issue time：2016年
We present the uniform and high-yield synthesis of a novel gold nanostructure of compass shape composed of a Au sphere at the central and two gradually thinning conical tips at opposed poles. The Au compass shapes were synthesized via a seed-mediated growth approach employing a binary mixture of cetyltrimethylammonium bromide (CTAB) and sodium oleate (NaOL) as the structure-directing agent. Under condition of single surfactant (CTAB), the spherical seeds tend to growth into bigger spherical Au nanoparticles (NPs); while the spherical seeds favor the formation of Au compass shaped NPs by using two mixed surfactants (CTAB/NaOL). The reaction kinetics clearly shows growth mechanism of Au compass shaped NPs. Interestingly, due to their anisotropic structure, Au compass shaped NPs show two distinctive plasmonic resonances, similar to those from Au nanorods (AuNRs). Particularly, the longitudinal surface plasmon resonances of Au compass shaped NPs exhibits a broadly tunable range from 600 to 865 nm. In addition, the obtained Au compass shaped NPs can be self-assembled into two dimensional (2D) monolayer with closely packed and highly aligned NPs, which results in periodic arrays of overlapped Au tips, generating hot spots for high-performance surface-enhanced Raman scattering (SERS).