Beyond Archimedean solids: Star polyhedral gold nanocrystals
Beyond Archimedean solids: Star polyhedral gold nanocrystals
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DOI：
10.1016/j.jcrysgro.2005.09.060
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发表时间：
2005-12-15
影响因子：
1.8
通讯作者：
Jose-Yacaman, M
中科院分区：
文献类型：
--
作者：
Burt, JL;Elechiguerra, JL;Jose-Yacaman, M
报道了在常温下用抗坏血酸在水中胶体还原合成星形多面体金纳米晶。我们确定了两类不同的恒星纳米晶体：具有五重对称性的多孪晶晶体和单晶。它们分别对应于二十面体和立方八面体这两种阿基米德固体，它们的{111}面优先生长。由于这种择优生长，原始阿基米德固体的{111}面生长成为四面体金字塔，每个金字塔的底部是原始多面体的面。通过采用星形形貌，金纳米晶增加了其裸露的{111}表面的比例，在面心立方晶体的低指数晶面中具有最低的表面能量。因此，我们提出恒星纳米晶体形成的驱动力可能是晶体表面能的降低。有趣的是，二十面体衍生的恒星纳米晶体具有与巨大的星状十二面体非常相似的几何形态，即开普勒-庞索固体。(C)2005 Elsevier B.V.保留所有权利。
We report star polyhedral gold nanocrystals synthesized by colloidal reduction with ascorbic acid in water at ambient conditions. We identify two distinct classes of star nanocrystals: multiple-twinned crystals with fivefold symmetry, and monocrystals. These respective classes correspond to icosahedra and cuboctahedra, two Archimedian solids, with preferential growth of their {111} surfaces. Due to this preferential growth, the {111} faces of the original Archimedean solids grow to become tetrahedral pyramids, the base of each pyramid being the original polyhedral face. By assuming a star morphology, gold nanocrystals increase their proportion of exposed {111} surfaces, which possess the lowest surface energy among low-index crystallographic planes for FCC crystals. Thus, we propose that the driving force for star nanocrystal formation Could be the reduction in surface energy that the crystals experience. Interestingly, icosahedrally derived star nanocrystals possess a geometric morphology closely resembling the great stellated dodecahedron, a Kepler-Poinsot solid. (c) 2005 Elsevier B.V. All rights reserved.