Optical Properties of Ultrashort Semiconducting Single-Walled Carbon Nanotube Capsules Down to Sub-10 nm

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• 作者：Xiaoming Sun ; Sasa Zaric ; Dan Daranciang ; Kevin Welsher ; Yuerui Lu ; Xiaolin Li ; Hongjie Dai
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：May 21, 2008
• 年：2008
• 卷：130
• 期：20
• 页码：6551 - 6555
• 全文大小：1236K
• 年卷期：v.130,no.20(May 21, 2008)
• ISSN：1520-5126

文摘

Single-walled carbon nanotubes (SWNTs) are typically long (100 nm) and have been well established as novel quasi one-dimensional systems with interesting electrical, mechanical, and optical properties. Here, quasi zero-dimensional SWNTs with finite lengths down to the molecular scale (7.5 nm in average) were obtained by length separation using a density gradient ultracentrifugation method. Different sedimentation rates of nanotubes with different lengths in a density gradient were taken advantage of to sort SWNTs according to length. Optical experiments on the SWNT fractions revealed that the UV−vis−NIR absorption and photoluminescence peaks of the ultrashort SWNTs blue-shift up to ~30 meV compared to long nanotubes, owing to quantum confinement effects along the length of ultrashort SWNTs. These nanotube capsules essentially correspond to SWNT quantum dots.