Purity assessment of multiwalled carbon nanotubes by Raman spectroscopy

Carbonaceous purity assessment for chemical vapor deposition multiwalled carbon nanotubes (MWNTs) using Raman spectroscopy was investigated. Raman spectroscopy was performed on a reference sample set containing predetermined ratios of MWNTs and representative synthesis by-products. Changes in the characteristic Raman peak ratios (i.e., I-D/I-G, I-G(')/I-G, and I-G(')/I-D) as a function of MWNT content were measured. Calibration curves were generated from the reference samples and used to evaluate MWNTs synthesized under different conditions with varying purity. The efficacy of using Raman spectroscopy in conjunction with thermogravimetric analysis for quantitative MWNT purity assessment is discussed. (c) 2007 American Institute of Physics.