title: Engineering Gold Nanoparticles in Compass Shape with Broadly Tunable Plasmon Resonances and High-Performance SERS.
abstract: 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 the opposed poles. The Au compass shapes were synthesized through a seed-mediated growth approach employing a binary mixture of cetyltrimethylammonium bromide (CTAB) and sodium oleate (NaOL) as the structure-directing agents. Under the condition of single surfactant (CTAB), the spherical seeds tend to grow into larger spherical Au nanoparticles (NPs); while the spherical seeds favor the formation of Au compass shaped NPs using two mixed surfactants (CTAB/NaOL). The reaction kinetics clearly shows a 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. Particularly, the longitudinal surface plasmon resonances of Au compass shaped NPs exhibit a broadly tunable range from 600 to 865 nm. In addition, the obtained Au compass shaped NPs can be self-assembled into a two-dimensional 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.
authors.affiliation: Division of Polymer and Composite Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, P. R. China.
authors.forename: Youju
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Division of Polymer and Composite Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, P. R. China.
authors.forename: Liwei
authors.initials: L
authors.lastname: Dai
authors.affiliation: Division of Polymer and Composite Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, P. R. China.
authors.forename: Liping
authors.initials: L
authors.lastname: Song
authors.affiliation: Division of Polymer and Composite Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, P. R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Division of Polymer and Composite Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, P. R. China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Rong
authors.affiliation: Division of Polymer and Composite Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, P. R. China.
authors.forename: Jiawei
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742-4454, United States.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Nie
authors.affiliation: Division of Polymer and Composite Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, P. R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
keywords: compass shape; gold nanoparticles; plasmon resonances; seed-mediated growth; self-assemble; surface-enhanced Raman scattering