High-yield synthesis of single-walled carbon nanotubes by gravity-free arcdischarge

Single-walled carbon nanotubes (SWNTs) have been produced in high yield by the dc arc discharge technique under gravity-free conditions. Gravity-free conditions can reduce the convection flow of the buffer gas during the arc discharge, which results in the increase of high thermostatic volume around the arc flame. The yields of both the total soot and SWNTs in soot are sig nificantly increased. Raman spectroscopy and transmission electron microsco py analyses reveal that the diameter distribution of SWNTs has shifted to a larger diameter region under the gravity-free condition. The annealing pro cess in high-thermostatic atmosphere is a crucial experimental factor to se lectively synthesize a certain diameter SWNT in high yield. (C) 2001 Americ an Institute of Physics.