Fully Alloyed Ag/Au Nanospheres: Combining the Plasmonic Property of Ag with the Stability of Au

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• 作者：Chuanbo Gao ; Yongxing Hu ; Mingsheng Wang ; Miaofang Chi ; Yadong Yin
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：May 21, 2014
• 年：2014
• 卷：136
• 期：20
• 页码：7474-7479
• 全文大小：442K
• 年卷期：v.136,no.20(May 21, 2014)
• ISSN：1520-5126

文摘

We report that fully alloyed Ag/Au nanospheres with high compositional homogeneity ensured by annealing at elevated temperatures show large extinction cross sections, extremely narrow bandwidths, and remarkable stability in harsh chemical environments. Nanostructures of Ag are known to have much stronger surface plasmon resonance than Au, but their applications in many areas have been very limited by their poor chemical stability against nonideal chemical environments. Here we address this issue by producing fully alloyed Ag/Au nanospheres through a surface-protected annealing process. A critical temperature has been found to be around 930 掳C, below which the resulting alloy nanospheres, although significantly more stable than pure silver nanoparticles, can still gradually decay upon extended exposure to a harsh etchant. Nanospheres annealed above the critical temperature show a homogeneous distribution of Ag and Au, minimal crystallographic defects, and the absence of structural and compositional interfaces, which account for the extremely narrow bandwidths of the surface plasmon resonance and may enable many plasmonic applications with high performance and long lifetime, especially for those involving corrosive species.