Ultrashort Single-Walled Carbon Nanotubes: Density Gradient Separation, Optical Property, and Mathematical Modeling Study

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• 作者：Yun Kuang ; Junfeng Liu ; Xiaoming Sun
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 26, 2012
• 年：2012
• 卷：116
• 期：46
• 页码：24770-24776
• 全文大小：571K
• 年卷期：v.116,no.46(November 26, 2012)
• ISSN：1932-7455

文摘

The density gradient ultracentrifuge separation (DGUS) method for obtaining ultrashort single-walled carbon nanotubes (SWNTs) was systematically investigated. A twice separation was used for further narrowing the length distribution. Investigations on Raman and absorbance spectra evidenced the concomitant chirality separation of the NTs. The length-dependent blue shift recorded on the absorbance spectra confirmed band gap widening on finite semiconductive SWNTs, which showed a linear relationship to the inverse of the length of the NTs. Laser ablation NTs were used to demonstrate DGUS as a general method for separation of different type of SWNTs. A possible vertical sedimentation separation mechanism is proposed, and a mathematical model was set up to give a quantitive description on separation results, which was further demonstrated by time-dependence experiments.