Hollow Gold-Silver Double-Shell Nanospheres: Structure, Optical Absorption, and Surface-Enhanced Raman Scattering
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- 作者：Tammy Y. Olson ; Adam M. Schwartzberg ; Christine A. Orme ; Chad E. Talley ; Breanna O'Connell ; Jin Z. Zhang
- 刊名：Journal of Physical Chemistry C
- 出版年：2008
- 出版时间：April 24, 2008
- 年：2008
- 卷：112
- 期：16
- 页码：6319 - 6329
- 全文大小：1078K
- 年卷期：v.112,no.16(April 24, 2008)
- ISSN：1932-7455
文摘
Hollow gold-silver double-shell nanospheres (AuAgHNSs) have been synthesized and their structural, optical,and single-particle surface-enhanced Raman scattering (SERS) properties characterized. The structure of theseAuAgHNSs have been determined by transmission electron microscopy (TEM), revealing a uniform silverouter shell of approximately 3 nm deposited by seed-mediated growth on 28 ± 6.2 nm hollow gold nanospheres(AuHNSs). Their plasmon resonance combines the energies of both the silver and the gold shells, broadeningthe absorption profile, while their overall structure maintains a spherical shape. This property is useful forSERS and other applications that require small, spherical nanostructures and broad, tunable absorption. Themechanism of silver growth on AuHNSs and gold NPs is proposed as silver island formation before completeencapsulation. SERS studies of mercaptobenzoic acid (MBA) before and after silver deposition show a 4-5-fold enhancement over AuHNSs with little change in signal consistency, while solid NPs exhibit little or nosignal improvement. A change in the relative peak intensity in the MBA Raman spectrum before and aftersilver coating is attributed to the effect of orientation and binding of thiols to gold and silver surfaces.