title: Clean nanotube unzipping by abrupt thermal expansion of molecular nitrogen: graphene nanoribbons with atomically smooth edges.
abstract: We report a novel physicochemical route to produce highly crystalline nitrogen-doped graphene nanoribbons. The technique consists of an abrupt N(2) gas expansion within the hollow core of nitrogen-doped multiwalled carbon nanotubes (CN(x)-MWNTs) when exposed to a fast thermal shock. The multiwalled nanotube unzipping mechanism is rationalized using molecular dynamics and density functional theory simulations, which highlight the importance of open-ended nanotubes in promoting the efficient introduction of N(2) molecules by capillary action within tubes and surface defects, thus triggering an efficient and atomically smooth unzipping. The so-produced nanoribbons could be few-layered (from graphene bilayer onward) and could exhibit both crystalline zigzag and armchair edges. In contrast to methods developed previously, our technique presents various advantages: (1) the tubes are not heavily oxidized; (2) the method yields sharp atomic edges within the resulting nanoribbons; (3) the technique could be scaled up for the bulk production of crystalline nanoribbons from available MWNT sources; and (4) this route could eventually be used to unzip other types of carbon nanotubes or intercalated layered materials such as BN, MoS(2), WS(2), etc.
authors.affiliation: Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-853, Japan.
authors.forename: Aarón
authors.initials: A
authors.lastname: Morelos-Gómez
authors.forename: Sofia Magdalena
authors.initials: SM
authors.lastname: Vega-Díaz
authors.forename: Viviana Jehová
authors.initials: VJ
authors.lastname: González
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Tristán-López
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Cruz-Silva
authors.forename: Kazunori
authors.initials: K
authors.lastname: Fujisawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Muramatsu
authors.forename: Takuya
authors.initials: T
authors.lastname: Hayashi
authors.forename: Xi
authors.initials: X
authors.lastname: Mi
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Shi
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Fitri
authors.initials: F
authors.lastname: Khoerunnisa
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kaneko
authors.forename: Bobby G
authors.initials: BG
authors.lastname: Sumpter
authors.forename: Yoong Ahm
authors.initials: YA
authors.lastname: Kim
authors.forename: Vincent
authors.initials: V
authors.lastname: Meunier
authors.forename: Morinobu
authors.initials: M
authors.lastname: Endo
authors.forename: Emilio
authors.initials: E
authors.lastname: Muñoz-Sandoval
authors.forename: Mauricio
authors.initials: M
authors.lastname: Terrones