High-Efficiency Separation of Single-Wall Carbon Nanotubes by Self-Generated Density Gradient Ultracentrifugation

We report an efficient density gradient ultracentrifugation (DGU) method for separation of metallic and semiconducting single-walled carbon nanotubes (SWCNTs) using a self-generated density gradient. A uniform-density SWCNT dispersion (33% v/v in iodixanol) was used to completely fill a centrifuge tube. After ultracentrifugation, separation of the metallic and semiconducting SWCNTs was achieved with a purity comparable to that achieved by DGU using a steplike density gradient. Because the SWCNTs were dispersed within the entire tube during this procedure, a large amount of SWCNTs can be separated at one time.