Understanding the Formation of Pentagonal Cyclic Twinned Crystal from the Solvent Dependent Assembly of Au Nanocrystals into Their Colloidal Crystals
Understanding the Formation of Pentagonal Cyclic Twinned Crystal from the Solvent Dependent Assembly of Au Nanocrystals into Their Colloidal Crystals
复制标题
了解金纳米晶体依赖于溶剂组装成胶体晶体而形成五边形环状孪晶晶体
DOI：
10.1021/jz401682q
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发表时间：
2013-10-17
影响因子：
5.7
通讯作者：
Xie, Zhaoxiong
中科院分区：
文献类型：
--
作者：
Bao, Shixiong;Zhang, Jiawei;Xie, Zhaoxiong
由于存在高密度的孪晶缺陷和弥散的弹性应变，五角环状孪晶（PCT）结构可能比相应的单晶结构具有更迷人的性能。虽然有很多关于PCT纳米晶的报道，许多单金属和镍基合金，PCT结构的既定的生长机制仍然是不直接的，通常彼此不一致。本文以十二硫醇修饰的Au纳米晶为构筑单元，以Au纳米晶自组装成胶体晶体为结晶模型，发现晶体内聚能和表面自由能的竞争在PCT胶体晶体的形成中起着重要作用。通过合理地选择溶剂来调节晶体的内聚能，可以调节胶体晶体的结构。PCT结构更可能在结构单元之间的相互作用弱时形成，而单晶结构在相互作用强时形成。结果表明，热力学因素是五角循环孪生的起源。
Due to the presence of high-density twinned-defects and diffuse elastic strain, pentagonal cyclic twinning (PCT) structures may have more fascinating properties than the corresponding single crystalline structure. Although there are a lot of reports concerning the PCT nanocrystals of many monometals and bimetal alloys, the established growth mechanisms of PCT structures are still not straightforward and usually inconsistent with each other. In this Letter, using dodecanethiol-capped Au nanocrystals (NCs) as building blocks, taking self-assembly of Au NCs into their colloidal crystals as the crystallization model, we found the competition of crystal cohesive energy and surface free energy plays an important role in the formation of PCT colloidal crystal. By rationally selecting the solvent to tailor the crystal cohesive energy, the structure of the colloidal crystals can be tuned. PCT structures are more likely to form when the interaction between building blocks is weak, while the single crystal structure is formed when the interaction is strong. The results demonstrate that the thermodynamic factors are the origin of pentagonal cyclic twinning.