Size, Structure, and Helical Twist of Graphene Nanoribbons Controlled by Confinement in Carbon Nanotubes

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• 作者：Thomas W. Chamberlain ; Johannes Biskupek ; Graham A. Rance ; Andrey Chuvilin ; Thomas J. Alexander ; Elena Bichoutskaia ; Ute Kaiser ; Andrei N. Khlobystov
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：May 22, 2012
• 年：2012
• 卷：6
• 期：5
• 页码：3943-3953
• 全文大小：680K
• 年卷期：v.6,no.5(May 22, 2012)
• ISSN：1936-086X

文摘

Carbon nanotubes (CNTs) act as efficient 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 efficient 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.

Keywords:

carbon nanotube; graphene nanoribbon; nanoreactor; host鈭抔uest structure; aberration-corrected high-resolution transmission electron microscopy