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- Yao, Mingguang, et al.
(author)
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Raman signature to identify the structural transition of single-wall carbon nanotubes under high pressure
- 2008
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In: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 78:20
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Journal article (peer-reviewed)abstract
- Raman spectra of single-walled carbon nanotubes (SWNTs) with diameters of 0.6–1.3 nm have been studied under high pressure. A “plateau” in the pressure dependence of the G-band frequencies was observed in all experiments, both with and without pressure transmission medium. Near the onset of the G-band plateau, the corresponding radial breathing mode (RBM) lines become very weak. A strong broadening of the full width at half maximum of the RBMs just before the onset of the G-band plateau suggests that a structural transition starts in the SWNTs. Raman spectra from SWNTs released from different pressures also indicate that a significant structural transition occurs during the G-band plateau process. Simulations of the structural changes and the corresponding Raman modes of a nanotube under compression show a behavior similar to the experimental observations. Based on the experimental results and the theoretical simulation, a detailed model is suggested for the structural transition of SWNTs, corresponding to the experimentally obtained Raman results in the high-pressure domain.
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| 2. |
- Liu, Bingbing, et al.
(author)
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High pressure and high temperature induced polymeric C60 nanocrystal
- 2008
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In: Diamond and related materials, vol. 17, issue 4-5. - Amsterdam : Elsevier B.V.. ; , s. 620-623
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Conference paper (peer-reviewed)abstract
- In this paper, C60 nanosheets with polymeric phases have been obtained under various high pressures and high temperatures, including orthorhombic and tetragonal polymeric phases. The structures have been identified and compared with those of nanorods by photoluminescence and Raman spectroscopies. The main fluorescence band shifted from 1.70 eV in the monomeric phase to near infrared in the polymeric phase when pressure and temperature were increased. The difference of photoluminescence and Raman spectra between nanosheets and nanorods samples treated under the same conditions is probably caused by different polymerization degree in these samples because of different shapes.
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