title: A diameter-selective attack of metallic carbon nanotubes by nitronium ions.
abstract: We have found a method for a diameter-selective removal of metallic single-walled carbon nanotubes (m-SWCNTs) from semiconducting (s-) ones by stirring or sonicating SWCNT powder in tetramethylene sulfone (TMS)/chloroform solution with nitronium hexafluoroantimonate (NO2SbF6: NHFA) and nitronium tetrafluoroborate (NO2BF4: NTFB). Positively charged nitronium ions (NO2+) were intercalated into nanotube bundles, where the intercalation was promoted also by the counterions. Nitronium ions selectively attacked the sidewall of the m-SWCNTs due to the abundant presence of electron density at the Fermi level, thus yielding stronger binding energy as compared to the counterpart s-SWCNTs. The s-SWCNTs were left on the filter after filtration, whereas the m-SWCNTs were disintegrated and drained away as amorphous carbons. The effectiveness of removing m-SWCNTs was confirmed by the resonant Raman spectra and absorption spectra.
authors.affiliation: BK21 Physics Division, Institute of Basic Science, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan University, Suwon 440-746, Korea.
authors.forename: Kay Hyeok
authors.initials: KH
authors.lastname: An
authors.forename: Jin Sung
authors.initials: JS
authors.lastname: Park
authors.forename: Cheol-Min
authors.initials: CM
authors.lastname: Yang
authors.forename: Seung Yol
authors.initials: SY
authors.lastname: Jeong
authors.forename: Seong Chu
authors.initials: SC
authors.lastname: Lim
authors.forename: Chul
authors.initials: C
authors.lastname: Kang
authors.forename: Joo-Hiuk
authors.initials: JH
authors.lastname: Son
authors.forename: Mun Seok
authors.initials: MS
authors.lastname: Jeong
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Lee