Tuning Plasmon Resonance of Gold Nanostars for Enhancements of Nonlinear Optical Response and Raman Scattering
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- 作者：Xiao-Li Liu ; Jia-Hong Wang ; Shan Liang ; Da-Jie Yang ; Fan Nan ; Si-Jing Ding ; Li Zhou ; Zhong-Hua Hao ; Qu-Quan Wang
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：May 8, 2014
- 年：2014
- 卷：118
- 期：18
- 页码：9659-9664
- 全文大小：340K
- 年卷期：v.118,no.18(May 8, 2014)
- ISSN：1932-7455
文摘
Localized surface plasmon resonances (LSPRs) of metal nanostructures are highly related to the shape, which could greatly enhance the light鈥搈atter interaction at nanoscale. Here, we investigate the LSPRs of gold nanostars corresponding to the unique morphology and demonstrate surface-enhanced Raman scattering (SERS) activities and nonlinear refraction properties of two typical structures. By adjusting the synthesis condition, the main plasmon resonance could be tuned from 557 to 760 nm. The plasmon modes and intense field enhancement near the sharp tips are revealed by finite-difference timed-domain (FDTD) simulations. The nonlinear refractive index |纬| reaches to the maximum value when the excitation wavelength is resonant to the LSPRs wavelength. The maximum value of |纬| for long-branched nanostars (位SP = 706 nm) is 5.843 脳 10鈥? cm2/GW, which is about 1.5 times larger than that of spherical-like nanostars with 位SP = 563 nm. The SERS activity of long-branched nanostars is about 15 times larger than that of spherical-like gold nanostars.