Characterizing the Chiral Index of a Single‐Walled Carbon Nanotube

Abstract

The properties of single-walled carbon nanotubes (SWCNTs) mainly depend on their geometry. However, there are still formidable difficulties to determine the chirality of SWCNTs accurately. In this review, some efficient methods to characterize the chiral indices of SWCNTs are illuminated. These methods are divided into imaging techniques and spectroscopy techniques. With these methods, diameter, helix angle, and energy states can be measured. Generally speaking, imaging techniques have a higher accuracy and universality, but are time-consuming with regard to the sample preparation and characterization. The spectroscopy techniques are very simple and fast in operation, but these techniques can be applied only to the particular structure of the sample. Here, the principles and operations of each method are introduced, and a comprehensive understanding of each technique, including their advantages and disadvantages, is given. Advanced applications of some methods are also discussed. The aim of this review is to help readers to choose methods with the appropriate accuracy and time complexity and, furthermore, to put forward an idea to find new methods for chirality characterization.

Chemical vapor deposition synthesis of near-zigzag single-walled carbon nanotubes with stable tube-catalyst interface

“…Furthermore, besides the ( n , m ) index, the structure of an SWNT can be indicated by other methods. By a simple polar coordinate transformation, ( n , m ) can be transferred into ( D ,θ) with the following equation ( 33 ) in which D refers to the diameter of an SWNT, θ refers to the helix angle, and a c-c refers to the length of the carbon-carbon bond. From the equation, we can see that the structure of an SWNT could be controlled by the diameter and the helix angle.…”

Accurate control of the covalent functionalization of single-walled carbon nanotubes for the electro-enzymatically controlled oxidation of biomolecules

“…The STEM image simulations were done using the software Nanotube Modeler (JCrystalSoft) and Vesta 3 for the atomic model generation [ 37 ] and QSTEM [ 38 ] for the STEM image simulations. SWCNT chiral indices were assigned by analysis of the Fourier-transform of the HRSTEM images and by comparing the images to simulations [ 39 – 40 ].…”

Electronic modulations in a single wall carbon nanotube induced by the Au(111) surface reconstruction

“…This nanotube was identified as a (6,5) semiconducting type, with a diameter of 0.75 nm and a band gap of 1.1 eV. 58 A line profile along the top of the tube (Figure 1(c)) shows long-range oscillations of the same period as the reconstruction pattern (6.3/cos(15 ) 6.5 nm). The apparent height of the tube is larger by about 0.3 Å over fcc regions than over hcp ones.…”