文摘
Single crystalline gold nanorods (Au NRs) dominated by {110} side facets were employed as seeds to tailor thedeposition of Ag. Apart from homogeneous coating, anisotropic coating of Ag was observed and resulted in an orangeslice-like shape for the Au@Ag nanocrystal. Different growth rates for the {110} side facets were responsible forthis shape: among the four {110} facets, two of the neighboring {110} facets grew more quickly and another twogrew more slowly, thus inducing the anisotropic deposition of Ag around the Au NR. This growth behavior is believedto 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 theanisotropic coating remains to be clarified, our results lead to one important conclusion: The interaction of CTABand metal can be utilized to tune the shapes of bimetallic structures.