Galvanically Replaced Hollow Au鈥揂g Nanospheres: Study of Their Surface Plasmon Resonance

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• 作者：Yoonjung Choi ; Soonchang Hong ; Lichun Liu ; Seong Kyu Kim ; Sungho Park
• 刊名：Langmuir
• 出版年：2012
• 出版时间：April 24, 2012
• 年：2012
• 卷：28
• 期：16
• 页码：6670-6676
• 全文大小：423K
• 年卷期：v.28,no.16(April 24, 2012)
• ISSN：1520-5827

文摘

We synthesized hollow Au鈥揂g nanospheres (NSs) by employing a galvanic replacement reaction between HAuCl₄ and Ag NSs. Uniform Ag NSs with controllable sizes were synthesized as sacrificial templates by a seed-mediated strategy. The atomic ratio of Au to Ag in Au鈥揂g NSs was tunable by controlling the reagent concentration. UV鈥搗is extinction spectra acquired from well-dispersed colloidal NS solutions were used to investigate the optical properties of the solutions. In addition to a common dipole mode exhibited on most transition metal nanoparticles, we observed a quadrupole plasmon resonance mode when the diameters of the Ag and Au鈥揂g NSs were larger than 100 nm. The quadrupole and dipole peaks both shifted to longer wavelengths with increased Au content in Au鈥揂g NSs. The experimental observation of optical properties of hollow Au鈥揂g NSs was compared with the theoretical simulation using DDA calculation, showing a good agreement.