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Au nanocrystal superlattices: nanocrystallinity, vicinal surfaces, and growth processes†
Nanoscale ( IF 5.8 ) Pub Date : 2018-07-16 00:00:00 , DOI: 10.1039/c8nr04606a
Detlef-M. Smilgies 1, 2, 3, 4 , Ruipeng Li 1, 2, 3, 4 , Marie Paule Pileni 5, 6, 7, 8
Affiliation  

Vicinal Au supracrystal surfaces were prepared from Ausingle single domain nanocrystals (NCs), whereas by replacing Ausingle with their polycrystalline counterparts common low-energy supracrystal surfaces were produced. By analogy to atomic crystalline surfaces, we propose a mechanism to explain the formation of such unexpected supracrystal vicinal surfaces, composed of only Ausingle NCs which are non-compact (bct structure) with a coherent alignment of the atomic planes oriented along the [111] superlattice axis and a slight tilt configuration (8.1°) of NCs. In the presence of Co(ε) NCs, these Ausingle supracrystals lose both the slightly tilted configuration of NCs and their orientational order leading to a superlattice transition from bct to fcc. In contrast, supracrystals of Aupoly NCs are insensitive to the presence of Co(ε) NCs. These intriguing structural changes obtained with Ausingle compared to Aupoly supracrystals in the absence and presence of Co(ε) NCs could explain the formation of vicinal surfaces. Note that the solvent used to disperse the nanocrystals plays a key role in the formation of supracrystal vicinal surfaces. Here, a new analogy between supracrystals and atomic crystals is presented.

中文翻译:

金纳米晶超晶格:纳米晶度,邻近表面和生长过程

用Au单单畴纳米晶体(NCs)制备近邻Au超晶表面,而用多晶对应物替代Au Single则产生了常见的低能超晶表面。通过类似于原子晶体表面,我们提出了一种机制来解释这种意想不到的超晶界表面,该结构仅由非紧凑的金单个NC(bct结构)组成,原子平面沿[111]方向连贯排列。 ]超晶格轴和NC的微倾斜配置(8.1°)。在存在Co(ε)NC的情况下,这些Au超晶失去了NC的略微倾斜的构型及其取向顺序,导致从bctfcc的超晶格转变。相反,Au poly NCs的超晶体对Co(ε)NCs的存在不敏感。用Au获得这些有趣的结构改变单个相比于Au在不存在和Co的存在supracrystals(ε)的NC可以解释的邻位表面的形成。注意,用于分散纳米晶体的溶剂在超晶体毗连表面的形成中起关键作用。在这里,提出了超晶体和原子晶体之间的一个新的类比。
更新日期:2018-07-16
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