Single-walled carbon nanotubes Raman spectra

Figure 5.4 Raman spectra (Xf c= 1064 nm) of PPY/SWNT composites obtained by electropolymerization ofpyrrole on a SWNT film in HCI 0.5 M. Curve 1 corresponds to the SWNT film Raman spectrum. Curves 2-6 show the evolution of the Raman spectrum after 6, 2, 25, 50, and 100 cycles, respectively, carried out in the potential range (- -100 - -800) m V vs. SCE with a sweep rate of 100 mV s Curve 7 corresponds to the composites described by curve 6 after interaction with NH4OH 1 M solution. (Reprinted with permission from Diamond and Related Materials, Electrochemical and vibrational properties of single-walled carbon nanotubes in hydrochloric acid solutions by 5. Lefrant, M. Baibarac, I. Baltog et al., 14, 3-7, 873-880. Copyright (2005) Elsevier Ltd)...

Figure 15.8 Raman spectrum of Mg/PMF combustion residues under 0.02 MPa argon, indicating the radial breathing mode characteristic for single walled carbon nanotubes (SWCNTs).

Fig. 23. Experimental room temperature Raman spectrum from a sample consisting primarily of bundles or ropes of single-wall nanotubes with diameters near that of the (10,10) nanotube. The excitation laser wavelength is 514.5 nm. The inset shows the lineshape analysis of the vibrational modes near 1580 cm . SWNT refers to singlewall carbon nanotubes [195].

In Fig. 11 we show the Raman speetrum of earbo-naeeous soot eontaining l-2 nm diameter, singlewall nanotubes produeed from Co/Ni-eatalyzed carbon plasma[28). These samples were prepared at MER, Inc. The sharp line components in the spectrum are quite similar to that from the Co-catalyzed carbons. Sharp, first-order peaks at 1568 cm and 1594 cm , and second-order peaks at -2680 cm" and -3180 cm are observed, and identified with single-wall nanotubes. Superimposed on this spectrum is the contribution from disordered sp carbon. A narrowed, disorder-induced D-band and an increased intensity in the second-order features of this sample indicate that these impurity carbons have been partially graphitized (i.e., compare the spectrum of carbon black prepared at 850°C, Fig. Id, to that which has been heat treated at 2820°C, Fig. Ic). 

Fig. 11. Raman spectrum (T = 300 K) of arc-derived carbons containing single-wall nanotubes generated in a Ni/Co-catalyzed dc arc (after ref. [42 ).

An article by Dumont et al. (2002) appears to answer the question as to what are the origins of these G- and D-bands (that is how they develop from a parent feedstock), and is therefore well worth quoting at some length. Dumont et al. (2002) report that a carbonaceous material does not have to be graphitic to produce a G-band and conversely that a relatively well-ordered carbon could produce a D-band. An article by Dresselhaus et al. (2002) indicates the complexity (and therefore amount of contained information) within a Raman spectrum from single-walled nanotubes. 

Figure 37 Raman spectrum T = 300 K) of arc-derived carbons containing single-wall nanotubes generated in a Ni/Co-catalyzed dc arc [38]. (Reproduced from Carbon, 33, Eklund, R C., et aL, Vibrational modes of carbon nanotubes spectroscopy and theory, pp. 959-972. Copyright 1995, with permission from Elsevier Science.)...

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