Doping mechanism in single-wall carbon nanotubes studied by optical absorption

Jacquemin, R.; Kazaoui, Saïd; Yu, Deng‐Guang; Hassanien, A.; Minami, Nobutsugu; Kataura, Hiromichi; Achiba, Yohji

doi:10.1016/s0379-6779(00)00318-0

Cited by 59 publications

(63 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, if the applied potential moves to 2.45 V, the dopinggenerated band shifts to 1.3 eV because lower v s n states are activated. The final peak position is identical to that reported upon Cs-doping, [17,27] if we assume symmetric electronic structure. In other words, Br 2 is an insufficiently strong oxidant for depletion of deep singularities in the valence band (v s n ), but electrochemistry in ionic liquids allows such a strong oxidation easily.…”

Section: Cyclic Voltammetrysupporting

confidence: 80%

“…The exciting photons (energies 2.41 eV or 2.54 eV) resonate with the transition (v s 3 3c s 3 ) in tubes of diameters 1.2 ± 1.5 nm. [17,29,30] The overall intensities of the RBM and TM modes decrease as a result of both cathodic and anodic charging in ionic liquid (Figure 4 and (5)), which matches the behavior in aqueous [20,39,40] and aprotic [8,12,21] electrolyte solutions. By comparing Figure 4 with Figure 6 and Figure 5 with Figure 7, the tube-related modes in peapods show a similar response to electrochemical charging as those of empty tubes.…”

Section: Raman Spectroscopysupporting

confidence: 70%

“…This band can be assigned to doping-induced transitions within the partly-filled valence band (v s n 3v s 1 , v s n 3v s 2 ; nx3). [8,12,17,27] Such transitions were revealed by Kazaoui et al [17,27] in SWCNTs doped by Br 2 and Cs. They were reproduced in chemically (Li) [16] and electrochemically [8] doped SWCNTs and peapods.…”

Section: Cyclic Voltammetrymentioning

confidence: 75%

“…[12] The p-doping of SWCNTs by Br 2 generated a new NIR band at 1.07 eV. [17,27] The n-doping by Li or Cs generated new bands at 0.9 and 1.25 eV [16] or 1.3 eV, [17,27] respectively. The different peak positions for p-and n-doping was ascribed to asymmetry of the electronic structure of the SWCNT.…”

Section: Cyclic Voltammetrymentioning

confidence: 99%

“…This is close to the 1.07 eV-band generated by Br 2 -doping. [17,27] (The standard redox potential of Br 2 /Br À is 1.07 V, that is, about 0.7 V vs. Fc/Fc ). However, if the applied potential moves to 2.45 V, the dopinggenerated band shifts to 1.3 eV because lower v s n states are activated.…”

Section: Cyclic Voltammetrymentioning

confidence: 99%

See 4 more Smart Citations

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

Kavan

Dunsch

2003

ChemPhysChem

View full text Add to dashboard Cite

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.

show abstract

Section: Cyclic Voltammetrysupporting

confidence: 80%