Size, Structure, and Helical Twist of Graphene Nanoribbons Controlled by Confinement in Carbon Nanotubes
Size, Structure, and Helical Twist of Graphene Nanoribbons Controlled by Confinement in Carbon Nanotubes
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DOI：
10.1021/nn300137j
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发表时间：
2012-05-01
期刊：
影响因子：
17.1
通讯作者：
Khlobystov, Andrei N.
中科院分区：
文献类型：
--
作者：
Chamberlain, Thomas W.;Biskupek, Johannes;Khlobystov, Andrei N.
碳纳米管（CNTs）作为一种高效的纳米反应器，可以作为模板组装不同尺寸、结构和构象的硫封端石墨烯纳米带（S-GNRs）。热处理或80 keV的电子束有效地触发自发形成的纳米带的小含硫分子。S-GNR容易在内径在1和2 nm之间的CNT中形成。在这个最佳范围之外，窄于1 nm的纳米管没有足够的空间来容纳S-GNR的2D结构，而宽于2nm的纳米管不能为单向S-GNR生长提供有效的限制，因此两者都不能支持纳米取向物的形成。理论计算表明，纳米带的热力学稳定性取决于S-GNR边缘结构，在较小程度上，纳米带的宽度。对于类似宽度的纳米带，锯齿形S-GNRs的聚硫杂环多茂型边缘比扶手椅型S-GNRs的聚噻吩型边缘更稳定。边缘结构和宽度两者限定了S-GNR的电子性质，其可以从金属到半导体到绝缘体广泛变化。封装的S-GNRs表现出不同的动力学行为，包括纳米管内部的旋转，平移和螺旋扭曲，这提供了一种通过在纳米尺度上限制来控制石墨烯纳米管的电子性质的机制。
Carbon nanotubes (CNTs) act as effident nanoreactors, templating the assembly of sulfur-terminated graphene nanoribbons (S-GNRs) with different sizes, structures, and conformations. Spontaneous formation of nanoribbons from small sulfur-containing molecules is efficiently triggered by heat treatment or by an 80 keV electron beam. S-GNRs form readily in CNTs with internal diameters between 1 and 2 nm. Outside of this optimum range, nanotubes narrower than 1 nm do not have sufficient space to accommodate the 2D structure of S-GNRs, while nanotubes wider than 2 nm do not provide effident confinement for unidirectional S-GNR growth, thus neither can support nanoribbon formation. Theoretical calculations show that the thermodynamic stability of nanoribbons is dependent on the S-GNR edge structure and, to a lesser extent, the width of the nanoribbon. For nanoribbons of similar widths, the polythiaperipolycene-type edges of zigzag S-GNRs are more stable than the polythiophene-type edges of armchair S-GNRs. Both the edge structure and the width define the electronic properties of S-GNRs which can vary widely from metallic to semiconductor to insulator. The encapsulated S-GNRs exhibit diverse dynamic behavior, Including rotation, translation, and helical twisting Inside the nanotube, which offers a mechanism for control of the electronic properties of the graphene nanoribbon via confinement at the nanoscale.