Yongfu Lian

Mass-production of single-wall carbon nanotubes by arc discharge method

Abstract With a Y–Ni alloy composite graphite rod as anode for d.c. arc discharge, a cloth-like soot was produced, containing about 40% single wall carbon nanotubes (SWCNTs). By characterization with high resolution transmission electron microscope (HREM) and Raman spectroscopy, it is found that the SWCNTs have nearly the same diameter of 1.3 nm and belong to armchair (n, n) type carbon nanotubes (n=8, 9, 10 and 11). It is also proposed that a large temperature gradient and the addition of Y–Ni alloy in the anode are the two most important factors influencing the formation of SWCNTs.

High-yield preparation of endohedral metallofullerenes by an improved DC arc-discharge method

Abstract The soot containing endohedral metallofullerenes Mx@C2n(M=Y, La, Tb and Sm; x=1, 2, 3; n⩾30) has been prepared by DC arc-discharge method under improved conditions including high helium pressure, low electric current, large gap distance between electrodes and high atomic ratio of M/C, with MNi2 alloys instead of metal oxides or pure metals as the encaged metal source, followed with extraction by CS2. The raw soot and extracts were analyzed by laser desorption mass spectrometry and results show that the relative yields of metallofullerenes, even if the usually low yield ones, Sm@C74 and Sm@C84 for example, are rather high. Some possible reasons leading to the high yield preparation are discussed.

Single-wall carbon nanotube colloids in polar solvents

Stable single-wall carbon nanotube (SWCNT) colloids in polar solvents, such as water, ethanol, acetone and DMF, have been prepared and the third-order optical nonlinearity of the SWCNTs measured using the femtosecond optical Kerr effect.

High-yield preparation of dimetallofullerenes by the improved DC arc discharge method

Abstract The soot containing yttrium metallofullerenes was prepared by DC arc discharge method under novel conditions including the use of YNi 2 alloy, high helium static pressure and high Y:C ratio and extracted by CS 2 . The extract was enriched by column liquid chromatography on silica gel with a mixed solvent of 85% petroleum ether and 15% xylene, xylene and carbon disulfide as successive eluents. Mass spectra show that dimetallofullerenes with nearly no detectable monometallofullerenes were obtained in bulk quantities.

A Simple Method to Make Field Emitter Using Ropes of Single-Walled Carbon Nanotubes

Field emission characteristics of single-walled carbon nanotubes were studied by using a simple method in a field emission microscope. The nanotube emission gun works effectively at the room temperature under a threshold field as low as 3.9 mV/μm. A typical I-V relationship of field emission was obtained with a high current density. The observed stable bright spots on the fluorescent screen originate from an ensemble emission from micro-ropes of the single-walled carbon nanotubes.