A resonance Raman study of carboxyl induced defects in single-walled carbon nanotubes

Changes in the vibrational response of single-walled carbon nanotubes (SWCNTs) resulting from the introduction of structural defects on their body were studied using resonance Raman spectroscopy. Structural defects were introduced on the SWCNTs by subjecting them to carboxylation for different intervals of time. Various Raman modes were observed, including the D, G(+)/G(-), G' modes, and new defect induced modes were identified. Weaker vibrational modes corresponding to Stone-Wales defects with specific structures known as Haeckelites were identified. These modes were compared with the theoretically calculated modes and correlated to O(5,6,7) and R(5,7) Haeckelite structures. (C) 2010 Elsevier B.V. All rights reserved.