title: Aggregation effects on the Raman spectroscopy of dielectrophoretically deposited single-walled carbon nanotubes.
abstract: The effect of aggregation on surfactant-suspended individual single-walled carbon nanotube (SWNT) Raman spectroscopy has been explored in the context of dielectrophoretic separation. The Raman spectra of individual surfactant-suspended HiPco SWNTs deposited on a substrate and the same suspension deposited via dielectrophoresis were compared as a function of iterative aggregation states. The evolution of the samples' radial breathing modes and tangential modes at multiple excitation wavelengths (514, 633, and 785 nm) illustrates a direct correlation between changes in the Raman spectra and a broadening and downshifting of resonance transition energies. Dielectrophoresis samples exhibited Raman changes similar to control samples, indicating characterization of electronic separation is compromised by aggregation effects.
authors.affiliation: Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375, USA.
authors.forename: Lars M
authors.initials: LM
authors.lastname: Ericson
authors.forename: Pehr E
authors.initials: PE
authors.lastname: Pehrsson