Chiral-Selective Protection of Single-walled Carbon Nanotube Photoluminescence by Surfactant Selection

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• 作者：Timothy J. McDonald ; Jeffrey L. Blackburn ; Wyatt K. Metzger ; Garry Rumbles ; Michael J. Heben
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：December 6, 2007
• 年：2007
• 卷：111
• 期：48
• 页码：17894 - 17900
• 全文大小：406K
• 年卷期：v.111,no.48(December 6, 2007)
• ISSN：1932-7455

文摘

We study the effects of adding H₂O₂ to acid-purified and unpurified single-walled carbon nanotubes (SWNTs)in aqueous suspensions using photoluminescence (PL) and optical absorption spectroscopies. The addition ofH₂O₂ to suspensions of unpurified SWNTs results in a rapid (1-2 h) quenching of the photoluminescencefrom all tubes, whereas H₂O₂ addition to acid-purified SWNTs causes the nanotube PL to grow in intensityover a period of several days before decaying in a tube-specific manner that depends on the binding strengthof the surfactant sheath. With the appropriate choice of surfactants, the PL for specific acid-purified SWNTscan be protected such that novel mid-gap and phonon-assisted absorption and emission transitions can beobserved without the obscuring effects associated with emission from other nanotubes. The H₂O₂ treatmentalso results in a reduction of the high-energy absorption background that has been associated with eithercarbonaceous impurities or the SWNT -plasmon oscillation. An understanding of the related mechanismsleads to a new method for separating nanotubes by type based on selective oxidation followed by selectiveprecipitation. These findings offer the possibility of efficiently separating large quantities of nanotubes bychirality.