Ultracentrifugation of single-walled nanotubes

Single-walled carbon nanotubes (SWNTs) are high aspect ratio cylinders of carbon (∼1 nm in diameter) whose walls are one atomic layer thick and have an atomic arrangement analogous to graphite. The SWNT atomic structure is defined by a two-dimensional chiral vector whose components are specified by a pair of positive integers: (n,m). This chirality of the SWNT dictates its properties. Unfortunately, current methods for producing SWNTs lack control over chirality, leading to significant polydispersity in the properties of as-synthesized SWNTs. Consequently, the widespread use of SWNTs in electronics, photonics, and sensors has been limited by their inhomogeneity.