Elastic Strain Energy Effects in Faceted Decahedral Nanoparticles
Elastic Strain Energy Effects in Faceted Decahedral Nanoparticles
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DOI：
10.1021/jp310045g
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发表时间：
2013-01
影响因子：
3.7
通讯作者：
S. Patala;L. Marks;M. O. Cruz
中科院分区：
文献类型：
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作者：
S. Patala;L. Marks;M. O. Cruz
十面体形态是纳米粒子中常见的结构之一，具有折返性的表面修饰。虽然这些模体在热力学上只在很小的尺寸范围内稳定，但实验观察到它们可以长到更大的尺寸(100纳米到几微米)。虽然表面能起着重要的作用，但在较大尺寸时，弹性应变能的贡献是不可忽略的，而由于表面再入而产生的应力松弛效应则鲜为人知。本文用有限元分析方法计算了由错位缺陷引起的体应变能，并给出了由于形成再入表面而产生的松弛。与传统观点相反，位错应变能是几何形状的非平凡函数，并且一般随长宽比的增大而增大。与先前报道的结果相比，计算的应变能还导致稳定区域增加约50%。
Decahedral morphology, with re-entrant surface modifications, is one of the common structures observed in nanoparticles. These motifs, although thermodynamically stable only at very small size ranges, have been experimentally observed to grow up to much larger sizes (100 nm to several micrometers). Whereas the surface energy plays an important role, the contributions of the elastic strain energy are nonnegligible at larger sizes and the effect of stress relaxation due to re-entrant surface faceting is poorly understood. In this article, the volumetric strain energy due to the disclination defect is computed using finite element analysis and the relaxation due to the formation of re-entrant surfaces is shown. Contrary to conventional wisdom, the disclination strain energy is shown to be a nontrivial function of the geometry and in general increases with increasing aspect ratio. The computed strain energies also result in approximately 50% increase in the stability regime than the previously reported result...