Product Code: ICA13_M708

Structural Changes in Single-Walled Carbon Nanotubes Induced by Pulsed Laser Irradiation
Authors:
Jeonghong Ha, POSTECH; POHANG South Korea
Dongsik Kim, POSTECH; Pohang South Korea
Presented at ICALEO 2013

Carbon nanotubes (CNTs) have great electrical, mechanical and thermal properties compared to conventional materials. However, the naturally-bundled structure, lattice imperfections and impurities seriously limit their engineering applications. There have been attempts to use laser beams to remove the imperfections and impurities but the interaction between high-power laser pulses and CNT structures is still vaguely understood. In this work, the structural changes in single-walled carbon nanotubes (SWNTs) that are induced by pulsed laser irradiation under various environmental conditions are analyzed experimentally. A Ti:sapphire femtosecond laser (wavelength = 800 nm; full width at half maximum FWHM = 50 fs) and a KrF excimer laser (wavelength = 248 nm, FWHM = 25 ns) are employed to modify the structure of SWNTs by changing the laser fluence and pulse number in air, vacuum, and aqueous solutions. The morphological changes are analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Raman spectroscopy is employed to observe the laser-induced changes in atomic structure, with emphasis on removal of impurities, oxidation of the SWNTs and structural transformation. The results of this work provide fundamental data required for developing novel processes to modify the structures of SWNTs and/or to purify them