Determining the percentages of semi-conducting and metallic single-walled carbon nanotubes in bulk soot

✍ Scribed by Nancy S. Jacobsen; Paul Pantano

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 520 KB
• Volume: 49
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/j.carbon.2011.01.025

✦ Synopsis

A procedure is presented to determine the percentages of metallic and semi-conducting single-walled carbon nanotubes (SWCNTs) in as-produced soot synthesized by a cobalt/ molybdenum-catalyzed chemical vapor deposition (CVD) process. The procedure involves the acquisition of UV-Vis-NIR absorption spectra of solvent-suspended soot samples, and the key aspect is the use of a physically-based subtraction of the p-plasmon absorbance from the overall absorbance to ensure that the percentage of semi-conducting SWCNTs is not overstated. The improvement in accuracy using the procedure is demonstrated using two lots of soot with different amounts of non-tubular carbon (NTC) contaminants. The semi-conducting SWCNT percentage of the soot containing low NTC levels was 82 ± 3%, and this mean was overestimated by 4% when the p-plasmon absorbance was not subtracted. The semi-conducting SWCNT percentage of the soot containing higher NTC levels was 76 ± 9%, and this mean was overestimated by 6% without subtraction of the p-plasmon absorbance.