Diameter Analysis of Rebundled Single-Wall Carbon Nanotubes Using X-ray Diffraction: Verification of Chirality Assignment Based on Optical Spectra

The validity of optically determined chirality assignment of single-wall carbon nanotube (SWCNTs) was investigated by comparing X-ray diffraction (XRD) with photoluminescence (PL) analyses for CoMoCAT SWCNTs. After the PL measurement of well-isolated SWCNTs, the SWCNT bundles were constructed again by removing surfactant from the isolated SWCNTs for the XRD measurement of a completely identical sample. The XRD analysis revealed that the SWCNTs have a uniform diameter of 0.78 ± 0.06 nm, which agrees well with the chirality assignment by PL mapping. This agreement represents that the chirality-assigned PL intensity actually reflects their diameter distribution. Furthermore, the purity of rebundled SWCNTs was found to be extremely high through scanning electron microscopy, XRD measurement, thermogravimetric analysis, and Raman spectroscopy. The isolation−rebundling process can work as a method of purification.