Xiang Yanjuan, Wu Xiaochun, Liu Dongfang, Li Zhiyuan, Chu Weiguo, Feng Lili, Zhang Ke, Zhou Weiya, Xie Sishen
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Graduate School of the Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
Langmuir. 2008 Apr 1;24(7):3465-70. doi: 10.1021/la702999c. Epub 2008 Feb 23.
Single crystalline gold nanorods (Au NRs) dominated by {110} side facets were employed as seeds to tailor the deposition of Ag. Apart from homogeneous coating, anisotropic coating of Ag was observed and resulted in an orange slice-like shape for the Au@Ag nanocrystal. Different growth rates for the {110} side facets were responsible for this shape: among the four {110} facets, two of the neighboring {110} facets grew more quickly and another two grew more slowly, thus inducing the anisotropic deposition of Ag around the Au NR. This growth behavior is believed to be a consequence of competition between the strong stabilization of cetyltrimethylammomium bromide (CTAB) molecules to the {110} facets of Ag and minimization of the overall surface energy. Although the reason for the anisotropic coating remains to be clarified, our results lead to one important conclusion: The interaction of CTAB and metal can be utilized to tune the shapes of bimetallic structures.
以{110}侧面为主的单晶金纳米棒（Au NRs）被用作种子来调控银的沉积。除了均匀包覆外，还观察到了银的各向异性包覆，这使得Au@Ag纳米晶体呈现出橙片状的形状。{110}侧面不同的生长速率导致了这种形状：在四个{110}面中，两个相邻的{110}面生长得更快，另外两个生长得更慢，从而导致银在Au NR周围的各向异性沉积。这种生长行为被认为是十六烷基三甲基溴化铵（CTAB）分子对银的{110}面的强稳定作用与整体表面能最小化之间竞争的结果。尽管各向异性包覆的原因仍有待阐明，但我们的结果得出了一个重要结论：CTAB与金属的相互作用可用于调控双金属结构的形状。
