title: Water-Assisted Preparation of High-Purity Semiconducting (14,4) Carbon Nanotubes.
abstract: Semiconducting single-walled carbon nanotubes (s-SWNTs) with diameters of 1.0-1.5 nm (with similar bandgap to crystalline silicon) are highly desired for nanoelectronics. Up to date, the highest reported content of s-SWNTs as-grown is ∼97%, which is still far below the daunting requirements of high-end applications. Herein, we report a feasible and green pathway to use H2O vapor to modulate the structure of the intermetallic W6Co7nanocrystals. By using the resultant W6Co7nanocatalysts with a high percentage of (1 0 10) planes as structural templates, we realized the direct growth of s-SWNT with the purity of ∼99%, in which ∼97% is (14,4) tubes (diameter 1.29 nm). H2O can also act as an environmentally friendly and facile etchant for eliminating metallic SWNTs, and the content of s-SWNTs was further improved to 99.8% and (14,4) tubes to 98.6%. High purity s-SWNTs with even bandgap determined by their uniform structure can be used for the exquisite applications in different fields.
authors.forename: Feng
authors.initials: F
authors.lastname: Yang
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.forename: Jia
authors.initials: J
authors.lastname: Si
authors.forename: Xiulan
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Kuo
authors.initials: K
authors.lastname: Qi
authors.affiliation: School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China.
authors.forename: Chuanhong
authors.initials: C
authors.lastname: Jin
authors.forename: Zeyao
authors.initials: Z
authors.lastname: Zhang
authors.forename: Meihui
authors.initials: M
authors.lastname: Li
authors.forename: Daqi
authors.initials: D
authors.lastname: Zhang
authors.forename: Juan
authors.identifier: 0000-0001-5502-9351
authors.initials: J
authors.lastname: Yang
authors.forename: Zhiyong
authors.identifier: 0000-0003-1622-3447
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Xu
authors.forename: Lian-Mao
authors.initials: LM
authors.lastname: Peng
authors.affiliation: Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Xuedong
authors.initials: X
authors.lastname: Bai
authors.forename: Yan
authors.identifier: 0000-0002-3828-8340
authors.initials: Y
authors.lastname: Li
keywords: carbon nanotube; chemical vapor deposition; chirality; intermetallic catalysts; semiconducting