Carbon nanotube Raman spectrum

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].

Hiura et al. [23] observed two Raman lines in their spectrum of nested carbon nanotubes at 1574 (FWHM = 23 cm ) and at 2687 cm. It is interesting to note that their first-order peak at 1574 cm lies between, and is more than twice as broad, as either of the two first-order lines in identi-... 

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 ).

Raman scattering is one of the most useful and powerful techniques to characterize carbon nanotube samples. Figure 15.17 shows the Raman spectrum of a single SWNT [127]. The spectrum shows four major bands which are labeled RBM, D, G, and G. ... 

In another example [56] SWNT was modified with peroxytrifluoroacetic add (PTFAA). Raman spectrum of the carbon nanotubes after the FIFA A treatment shows a D-line substantially increased indicating the formation of defect sites with sp3-hybridized carbon atoms on the sidewalls due to the addition of the functional groups. The RBM bands in the region of 170-270cm-1 decreased and shifted to higher... 

With the aid of a bi-functionalized reagent (terminated with pyrenyl unit at one end and thiol group at the other end), gold nanoparticles were self-assembled onto the surface of solubilized carbon nanotubes [147], Raman spectrum of the gold nanoparticle bearing CNTs is enhanced possibly due to charge transfer interactions between nanotubes and gold nanoparticles. 

Figure 4. Raman spectrum of multi-walled carbon nanotubes after purification recorded for kexc. = 676.4 nm [22], The low frequency modes have been calculated as explained in the text.

As a typical example, Figure 12.15 shows the Raman spectra of an unfilled ethylene-propylene-diene rubber (EPDM). The Raman spectra of pure MWNTs, pure CB and of a EPDM / MWNTs composite are also given. The D, G and G bands are respectively located at 1348, 1577 and 2684 cm-1 in the Raman spectrum of the multiwall carbon nanotubes. The Raman spectrum of pure carbon black (CB) remains dominated by the bands associated with the D and G modes at 1354 and 1589 cm1 respectively, even when the carbons do not have particular graphiting ordering (Figure 12.11). This fact has been widely discussed by Robertson (84) and Filik (85). Amorphous carbons are mixtures of sp3 (as in diamond) and sp2 (as in graphite) hybridised carbon. The it bonds formed by the sp2 carbons being more polarisable than the a bonds formed by the sp3 carbons, the authors conclude that the Raman spectrum is dominated by the sp2 sites. 

We have developed solvothermal synthesis as an important method in research of metastable structures. In the benzene-thermal synthesis of nanocrystalline GaN at 280°C through the metathesis reaction of GaClj and U3N, the ultrahigh pressure rocksalt type GaN metastable phase, which was previously prepared at 37 GPa, was obtained at ambient condition [5]. Diamond crystallites were prepared from catalytic reduction of CCI4 by metallic sodium in an autoclave at 700°C (Fig.l) [6]. In our recent studies, diamond was also prepared via the solvothermal process. In the solvothermal catalytic metathesis reaction of carbides of transition metals and CX4 (X = F, Cl, Br) at 600-700°C, Raman spectrum of the prepared sample shows a sharp peak at 1330 cm" (Fig. 1), indicating existence of diamond. In another process, multiwalled carbon nanotubes were synthesized at 350°C by the solvothermal catalytic reaction of CgCle with metallic potassium (Fig. 2) [7]. 

Fig. 7.7 Comparison of Raman spectra for carbon nanotubes (1) and normalized G-bands of a single crystalline (2) polycrystalline anisotropic graphite sample with oriented grains and LaiSOO A (3) and the difference spectrum corresponding to the curves 2 and 3 (4). All spectra correspond to room temperature and excitation with > l=514.5 nm and are normalized to the maximum of the intensity of the corresponding Raman band. The difference spectrum (4) is multiplied by a factor of 3 for better comparison with the other spectra...

Figure 3.40 Separation of metallic and semiconducting carbon nanotubes by AC dielectrophoresis. (a) Scheme of the installation, and (b) Raman spectrum of a metallic sample in comparison to the starting material as reference ( AAAS 2003).

Carbon nanotubes respond to mechanical strain by a signal shift in the Raman spectrum. Especially the change of the G-band is proportional to the pressure and can be used to measure the latter. In a similar manner, nanotubes may serve as an indicator for strain in polymers. This is of particular interest with regard to... 

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)...

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