| 1. |
- Cui, Wen, et al.
(author)
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Synthesis of alkali-metal-doped C60 nanotubes
- 2011
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In: Diamond and Related Materials. - : Elsevier BV. ; , s. 93-96
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Conference paper (peer-reviewed)abstract
- C60 nanotubes have been synthesized by a solution–solution method. After degassing in a dynamic vacuum, the C60 nanotubes were doped with alkali metals by means of vapor evaporation method. Different temperatures have been studied to evaporate the alkali metals for the doping experiments. Raman spectrum was further employed to analyze the doping concentration of the obtained samples. It was found that all three alkali metals (Li, Na and K) used can be efficiently doped into the C60 nanotubes, forming AxC60 nanotubes. The doping concentration of Li, Na changed from low to high level, depending on the experiment temperatures, while K doping always gave saturated doping. The melt points, the ionic sizes and vapor pressures of alkali metals were thought to affect the final doping results.
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| 2. |
- Liu, Bingbing, et al.
(author)
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High-pressure induced polymerization of C60 nanorods
- 2005
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In: Proceedings of the Joint 20th AIRAPT and 43rd EHPRG Conf. on High Pressure Science and Technology, Karlsruhe 2005. - 3923704496 ; , s. Nanomat-O133
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Conference paper (other academic/artistic)abstract
- C60 nanorods, about 200 nm in diameter and several micrometers in length and with a rectangular cross section, have been synthesized by a simple solution-growth method. Raman spectroscopy and TEM indicate that the C60 nanorods have a fcc crystalline structure similar to that of pristine C60. Nanorods were polymerized at high temperature and high pressure below 2 GPa. Two different polymeric structures, orthorhombic and tetragonal as determined by Raman spectroscopy, have been obtained under different high temperature and high pressure conditions. The high-pressure induced polymeric samples keep the original nanometer scale rod shape.
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| 3. |
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| 4. |
- Liu, Dedi, et al.
(author)
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Synthesis and solid-state studies of self-assembled C60 microtubes
- 2011
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In: Diamond and Related Materials, vol. 20 issue 2. - : Elsevier BV. ; , s. 178-182
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Conference paper (peer-reviewed)abstract
- C60 microtubes were fabricated by a modified solution evaporation method, evaporating a solution of C60 in toluene in an atmosphere of m-xylene at room temperature. The C60 microtubes have outer diameters ranging from 2 to 8 μm. IR spectra, TG analysis and X-ray diffraction showed a solvated structure for the as-grown C60 microtubes. Through a gentle heat-treatment in vacuum, pure C60 microtubes with single crystalline fcc structure were obtained after the elimination of solvents. It is suggested that the C60 microtubes form through self-assembly from several individual C60 nanorods.
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| 5. |
- Sundqvist, Bertil, et al.
(author)
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Electrical transport properties of A4C60 (A=Li,Na,Rb) under pressure
- 2008
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In: High Pressure Research vol. 28 issue 4 December 2008. - London : Taylor & Francis. ; , s. 597-600
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Conference paper (peer-reviewed)abstract
- In search of structural phase transformations, the electrical resistances of the alkali metal-intercalated fullerene compounds Li4C60, Na4C60, and Rb4C60 have been measured as functions of temperature and pressure. The compounds have different lattice structures, and in the first two, the fullerene molecules form two-dimensional covalently bonded polymer lattices. No phase changes could be identified over the ranges 100-400 K and 0-2 GPa. All materials are semiconducting under the conditions studied, and we see no strong dependence of the band gaps on pressure.
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| 6. |
- Sundqvist, Bertil, et al.
(author)
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High pressure studies of alkali metal doped fullerides A4C60
- 2011
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In: Diamond and Related Materials, Volume 20, issue 4. - : Elsevier. ; , s. 600-603
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Conference paper (peer-reviewed)abstract
- The electrical resistance R of K4C60 and Li4C60 has been measured between 100 and 300 K under pressures up to 1 and 2 GPa, respectively. For both materials, the temperature coefficient of R is negative at all pressures and temperatures in this range. The transport properties of Li4C60 at low pressure are compatible with a recent observation of high ionic conductivity, but surprisingly, this conductivity term increases strongly with increasing pressure, contradicting an intuitive model. For K4C60 we see no sign of a recently suggested structural phase transformation at low temperature, nor can we find any convincing evidence for a lattice disproportionation as recently observed for Rb4C60.
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| 7. |
- Yao, Mingguang, et al.
(author)
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Reversible nano-scale phase separation of Rb4C60 under pressure
- 2010
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In: Journal of physics: conference series. - Bristol : Institute of Physics (IOP). ; , s. 012020-
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Conference paper (peer-reviewed)abstract
- The alkali fulleride Rb4C60 has been investigated by studies of the resistance and by Raman spectroscopy under pressures up to 2 GPa and 13 GPa, respectively. Our data show a reversible phase separation into metallic Rb3C60 and Rb6C60 at pressures above 1 GPa. The reversibility indicates that the phase separation primarily occurs on the nanometer length scale. The data explain several puzzling results reported in the recent literature.
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