Ultraviolet pulsed laser irradiation of multi-walled carbon nanotubes in nitrogen atmosphere

Altres ajuts: this work was supported by the Spanish National Research Council under the Contract Nos. 200960I015, 200860I211.Laser irradiation of randomly oriented multi-walled carbon nanotube (MWCNT) networks has been carried out using a pulsed Nd:YAG UV laser in nitrogen gas environment. The evolution of the MWCNT morphology and structure as a function of laser fluence and number of accumulated laser pulses has been studied using electron microscopies and Raman spectroscopy. The observed changes are discussed and correlated with thermal simulations. The obtained results indicate that laser irradiation induces very fast, high temperature thermal cycles in MWCNTs which produce the formation of different nanocarbon forms, such as nanodiamonds. Premelting processes have been observed in localized sites by irradiation at low number of laser pulses and low fluence values. The accumulation of laser pulses and the increase in the fluence cause the full melting and amorphization of MWCNTs. The observed structural changes differ from that of conventional high temperature annealing treatments of MWCNTs

Ultraviolet pulsed laser irradiation of multi-walled carbon nanotubes in nitrogen atmosphere

Under the terms of license Creative Commons Attribution (CC BY) license to their work.Laser irradiation of randomly oriented multi-walled carbon nanotube (MWCNT) networks has been carried out using a pulsed Nd:YAG UV laser in nitrogen gas environment. The evolution of the MWCNT morphology and structure as a function of laser fluence and number of accumulated laser pulses has been studied using electron microscopies and Raman spectroscopy. The observed changes are discussed and correlated with thermal simulations. The obtained results indicate that laser irradiation induces very fast, high temperature thermal cycles in MWCNTs which produce the formation of different nanocarbon forms, such as nanodiamonds. Premelting processes have been observed in localized sites by irradiation at low number of laser pulses and low fluence values. The accumulation of laser pulses and the increase in the fluence cause the full melting and amorphization of MWCNTs. The observed structural changes differ from that of conventional high temperature annealing treatments of MWCNTs.This work was supported by the Spanish National Research Council under the Contract Nos. 200960I015, 200860I211, and MAT2011-24757; the EU FP7-ITN RADDEL No. 290023; and the Executive Unit for Financing Higher Education, Research, Development, and Innovation of the Romanian Ministry of Education, Research, Youth, and Sports under the Contract No. PCE-2012-4-0292. L.C. acknowledges a JAE-Predoc fellowship (CSIC). L.C. is involved in the UAB PhD program.Peer Reviewe