Separation of gold nanorods using density gradient ultracentrifugation
Au nanorods, aspect ratio, density gradient, separation, surface-enhanced Raman scattering (SERS)
High quality gold nanorods (NRs) with a monodisperse size and aspect ratio are essential for many applications. Here, we describe how nearly monodisperse gold NRs can be separated from polydisperse samples using density gradient ultracentrifugation. Size and dimension analysis by transmission electron microscopy (TEM) and absorption spectroscopy revealed that the Au NRs were separated mainly as a function of their aspect ratio. The surface-enhanced Raman scattering (SERS) activity of Au NRs with lower aspect ratio is notably stronger than that of NRs with higher aspect ratio under 633 nm laser excitation, due to the size-dependent absorption of the longitudinal plasmon band. The separation approach provides a method to improve the quality of NRs produced by large scale synthetic methods.
Tsinghua University Press
Shuai Li,Zheng Chang,Junfeng Liu,Lu Bai,Liang Luo,Xiaoming Sun, Separation of gold nanorods using density gradient ultracentrifugation. NanoRes.2011, 4(8): 723–728