Single-wall carbon nanotubes: a high yield of tubes through laser ablation of a crude-tube target

In the purification of single-wall carbon nanotubes (SWNTs), it has been difficult to remove graphitic particles. We were able to increase the percentage of SWNTs and decrease impurities in the form of graphite particles and amorphous carbon by using a new target. The target material was made of crude SWNTs, which contains SWNTs (20–30%), particles of graphite (about 10–20%), amorphous carbon (50–60%) and a little of Ni and Co (about 0.6%). The high yield of SWNTs obtained was attributed to the composition of the target and its porous structure.