Silicon promotes the highest single-wall carbon nanotube purity in pulsed laser vaporization

Work with a dual pulsed laser vaporization (DPLV) system built for the synthesis of single-wall carbon nanotubes (SWCNT) indicates that a key factor in early reports of material purities thought at that time to be as high as 90%, originally attributed to reaction volume confinement by a small-diameter process tube was, at least in part, due rather to an unrecognized source of silicon in those early synthesis experiments. It is demonstrated that Si enhances the product purity by spectroscopic assay of DPLV synthesized product materials produced both with and without the purposeful inclusion of a small quantity of Si along with the Co/Ni catalysts into the targets. Such enhancement of the product purity on the inclusion of Si may find useful application in other methods of SWCNT production, most directly in carbon arc and plasma torch-based syntheses.