National Research Centre "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia.
Nanoscale. 2012 Aug 7;4(15):4522-9. doi: 10.1039/c2nr30144j. Epub 2012 Jun 13.
The dispersion-corrected density functional theory (DFT-D) is applied for investigation of structure and electronic properties of a sulfur-terminated graphene nanoribbon (S-GNR) encapsulated in a carbon nanotube. Two mechanisms of accommodation of the GNR in the carbon nanotube, distortion of the nanotube cross-section into an elliptic shape accompanied by bending of the GNR and transformation of the GNR to a helical conformation, are analyzed. Three types of elastic distortions of the nanotube and encapsulated GNR are revealed depending on the ratio of the diameter of the nanotube cavity to the GNR width. Helical states of the GNR are shown to be stabilized by the van der Waals attraction of sulfur atoms at neighbouring edges of adjacent turns of the GNR. The results of calculations are correlated with the experimental observations for the S-GNR synthesized recently inside the carbon nanotube. The hybrid DFT calculations of band structures of zigzag GNRs terminated with different atoms demonstrate that as opposed to O- and H-GNRs, the S-GNR is metallic even when deformed inside carbon nanotubes. Possible applications of GNRs encapsulated in carbon nanotubes are discussed.
应用含弥散修正的密度泛函理论（DFT-D）研究了一个被碳纳米管包裹的硫终止石墨烯纳米带（S-GNR）的结构和电子性质。分析了 GNR 被碳纳米管容纳的两种机制，即纳米管横截面变形为椭圆形并伴随 GNR 弯曲，以及 GNR 转变为螺旋构象。根据纳米管腔直径与 GNR 宽度的比值，揭示了三种类型的纳米管和封装 GNR 的弹性变形。通过相邻 GNR 螺旋转弯边缘处硫原子的范德华吸引力，稳定了 GNR 的螺旋态。计算结果与最近在碳纳米管内合成的 S-GNR 的实验观察结果相关联。用不同原子终止的锯齿形 GNR 的能带结构的杂化 DFT 计算表明，与 O-和 H-GNR 相反，即使在碳纳米管内变形，S-GNR 也是金属的。讨论了封装在碳纳米管内的 GNR 的可能应用。
