Size-Dependent Structure Relations between Nanotubes and Encapsulated Nanocrystals

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• 作者：Andrei A. Eliseev ; Nikolay S. FalaleevNikolay I. Verbitskiy ; Andrei A. VolykhovLada V. Yashina ; Andrei S. Kumskov ; Victoria G. Zhigalina ; Alexander L. Vasiliev ; Alexey V. Lukashin ; Jeremy Sloan ; Nikolay A. Kiselev
• 刊名：Nano Letters
• 出版年：2017
• 出版时间：February 8, 2017
• 年：2017
• 卷：17
• 期：2
• 页码：805-810
• 全文大小：426K
• ISSN：1530-6992

文摘

The structural organization of compounds in a confined space of nanometer-scale cavities is of fundamental importance for understanding the basic principles for atomic structure design at the nanolevel. Here, we explore size-dependent structure relations between one-dimensional PbTe nanocrystals and carbon nanotube containers in the diameter range of 2.0–1.25 nm using high-resolution transmission electron microscopy and ab initio calculations. Upon decrease of the confining volume, one-dimensional crystals reveal gradual thinning, with the structure being cut from the bulk in either a <110> or a <100> growth direction until a certain limit of ∼1.3 nm. This corresponds to the situation when a stoichiometric (uncharged) crystal does not fit into the cavity dimensions. As a result of the in-tube charge compensation, one-dimensional superstructures with nanometer-scale atomic density modulations are formed by a periodic addition of peripheral extra atoms to the main motif. Structural changes in the crystallographic configuration of the composites entail the redistribution of charge density on single-walled carbon nanotube walls and the possible appearance of the electron density wave. The variation of the potential attains 0.4 eV, corresponding to charge density fluctuations of 0.14 e/atom.