1Korea Electrotechnology Research Institute 2Kumoh National Institute of Technology 3Kumoh National Institute of Technology 4Georgia Institute of Technology
A method for evaluating bulk sensitive structural characteristics of unpurified, as-purified, and acid treated single walledcarbon nanotubes (SWNTs) was described in the present study. The optical spectra of SWNT solutions were well resolvedafter prolonged sonication and they were correlated to the diameter and the distribution of nanotubes. The acid-treatedSWNTs were similar to as-purified SWNTs in terms of catalyst residue, radial breathing mode (RBM) in the Raman spectra,and the first band gap energy of semiconducting tubes in the optical spectra. The solution phase optical spectra were moresensitive to changes in the small diameter and metallic tubes after the acid treatment than were the RBM spectra.