New Results in Chirality Sorting of Single-Walled Carbon Nanotubes by Density Gradient Ultracentrifugation
S. Ghosh, R.B. Weisman
Rice University, US
Keywords: single-walled carbon nanotubes, chirality sorting
Abstract:A major current goal in single-walled carbon nanotube (SWCNT) research is the sorting of polydisperse, as-grown samples into their separate structural species. Because nanotube electronic properties are governed by diameter and chiral angle (together called chirality), this type of sorting is essential for many applications. Hersam and co-workers first reported that the technique of density gradient ultracentrifugation (DGU) can be effective for nanotube chirality sorting.1 Since that report, DGU has emerged as the most promising approach in this area. We report here significant advances in DGU separation of SWCNTs. Beginning with a HiPco-grown sample containing a wide range of chiralities, we are able to obtain fractions highly enriched in any of eight different (n,m) species using only a single step of centrifugation. The chiral species that can be obtained in this way are: (8,3), (9,1), (6,5), (7,3), (7,5), (10,2), (7,6), and (8,6). Their diameters range from 0.706 nm to 0.966 nm. Absorption and fluorescence spectra of these separated fractions will be shown.