Smallest limit of tube diameters for encasing of particular fullerenes determined by radial breathing mode Raman scattering

1-butyl-3-methylimidazolium tetrafluoroborate (an ionic liquid) is an advantageous electrolyte for the study of charge-transfer reactions at single-walled carbon nanotubes (SWCNTs) and fullerene peapods (C 60 @SWCNT). Compared to traditional electrolyte solutions, this medium offers a broader window of electrochemical potentials to be applied, and favorable optical properties for in situ Vis/NIR and Raman spectroelectrochemistry of nano-carbon species. The electrochemistry of both nanotubes and peapods is dominated by their capacitive double-layer charging. Vis/NIR spectroelectrochemistry confirms the charging-induced bleaching of transitions between Van Hove singularities. At high positive potentials, new optical transitions were activated in partly filled valence band. The bleaching of optical transitions is mirrored by the quenching of resonance Raman scattering in the region of tube-related modes. The Raman frequency of the tangential displacement mode of SWCNT shifts to blue upon both anodic and cathodic charging in the ionic liquid. The Raman modes of intratubular C 60 exhibit a considerable intensity increase upon anodic doping of peapods.

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“…The diameter of the SWCNT (d) is known to scale with the RBM frequency (w) as in Equation (4): [19,31] d % k/w (4)…”

Section: Raman Spectroscopymentioning

confidence: 99%

“…[19,31,37,38] Equation (4) yields d between 1.2 ± 1.5 nm for w between 185 to 165 cm À1 (cf. Figure 4 and 5), which is close to the diameters estimated from Vis/NIR spectra (Section 3.2).…”

Section: Raman Spectroscopymentioning

confidence: 99%

Ionic Liquid for in situ Vis/NIR and Raman Spectroelectrochemistry: Doping of Carbon Nanostructures

Kavan

Dunsch

2003

ChemPhysChem

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“…Possible techniques for fabricating DWNTs include chemical vapor deposition (CVD) [1,2] or the filling of SWNTs with fullerenes that coalesce and form inner tubes upon heat treatment [3,4]. Both types of DWNTs are studied in the present work and are inter-compared.…”

Section: Introductionmentioning

confidence: 99%

Wall-to-wall stress induced in (6,5) semiconducting nanotubes by encapsulation in metallic outer tubes of different diameters: A resonance Raman study of individual C60-derived double-wall carbon nanotubes

et al. 2010

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We measure resonant Raman scattering from 11 individual C 60 -derived double wall carbon nanotubes with inner semiconducting (6,5) tubes and outer metallic tubes. The Raman spectra show the radial breathing mode (RBM) of the inner and the outer tubes simultaneously in resonance with the same laser energy. We observe that an increase in the RBM frequency of the inner tubes is related to an increase in the RBM frequency of the outer tubes. The Raman spectra also contain a sharp G − feature that increases in frequency as the nominal diameter of the outer metallic tubes decreases. Finally, the one phonon second-order D band mode shows a two way frequency splitting that decreases with decreasing nominal wall to wall distances. We suggest that the stress which increases with decreasing nominal WtW distances is responsible for the observed hardening of the frequencies of the RBM, D an G − modes of the inner (6,5) semiconducting tubes.

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“…5 shows that larger tubes exhibit higher filling rates. This conclusion is supported by the report that larger tubes are energetically preferable for encapsulating diacety-lene chains [27].The smallest tube diameter for encapsulation, which is determined by the size and affinity between tubes and molecules, has been investigated [28]. Here, any lower or upper limit of the diameter could not be found for encapsulation.…”

Section: Resultsmentioning

confidence: 56%

Structural Analysis of Encapsulated Single-Walled Carbon Nanotubes

Singh¹,

Shukla²,

Kumar³

et al. 2015

SIJSMS

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Tip-enhanced Raman spectroscopy revealed the nanoscale chemical properties of organic molecules encapsulated in single walled carbon nanotubes (SWNTsanalysis focuses is more on structural information, such as intermolecular interactions, molecular orientations, and symmetry distortions of each species. Moreover, vibrational spectroscopy can be used for identifying molecular species, which is not possible by TEM. Therefore, Raman spectroscopy is a powerful tool for studying the chemical composition of matter. Conventional confocal Raman spectroscopy techniques are limited to sub wavelength spatial resolution, and localized vibrational features of molecules encapsulated in SWNTs have not been resolved so far. This limitation has been overcome by the development of tip-enhanced Raman spectroscopy (TERS) [8][9][10][11][12][13][14][15][16]. By introducing a sharp metal tip to the focus of a laser beam, we were able to localize Raman excitation to an area of 30 nm 2 [17][18][19]. This technique has recently enabled the molecular nanoimaging of a single carbon nanotube [20] and double-stranded DNA network structures [21].

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Smallest limit of tube diameters for encasing of particular fullerenes determined by radial breathing mode Raman scattering

Cited by 102 publications

References 14 publications

Ionic Liquid for in situ Vis/NIR and Raman Spectroelectrochemistry: Doping of Carbon Nanostructures

Ionic Liquid for in situ Vis/NIR and Raman Spectroelectrochemistry: Doping of Carbon Nanostructures

Wall-to-wall stress induced in (6,5) semiconducting nanotubes by encapsulation in metallic outer tubes of different diameters: A resonance Raman study of individual C60-derived double-wall carbon nanotubes

Structural Analysis of Encapsulated Single-Walled Carbon Nanotubes

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