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Doping in covalently functionalized carbon nanotubes: A Raman scattering study
Author(s) -
Gordeev Georgy,
Setaro Antonio,
Glaeske Mareen,
Jürgensen Sabrina,
Reich Stephanie
Publication year - 2016
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201600636
Subject(s) - surface modification , raman spectroscopy , materials science , carbon nanotube , doping , raman scattering , phonon , covalent bond , fermi level , optical properties of carbon nanotubes , absorption (acoustics) , luminescence , selective chemistry of single walled nanotubes , nanotechnology , nanotube , optoelectronics , chemistry , composite material , condensed matter physics , optics , organic chemistry , physics , quantum mechanics , electron
We experimentally investigate the effect of the structural and optoelectronic changes carbon nanotubes undergo after covalent functionalization. The carboxylation process alters the crystalline structure and the optical response of the tubes. We analyzed the intensity of disorder modes in the Raman spectra to estimate the structural degradation of the sp 2 network. After functionalization the bands associated with the G and 2D mode shift to higher frequency, indicating a change of the Fermi level Δ E F ∼ −0.5 and −0.65 eV in semiconducting and metallic nanotubes. This is also corroborated by the broadening of the semiconducting and narrowing of the metallic G mode phonons. Analysis of the luminescence correlated with absorption spectroscopy suggests that only the large‐diameter tubes remain present after the functionalization procedure, whereas the small‐diameter ( d < 8.2 Å) ones get destroyed in the process. The spectral shifts of the E 11 transition energies indicate uniaxial strain of ( ϵ = 0.18%) in the semiconducting nanotubes due to functionalization.