Retention of Intrinsic Electronic Properties of Soluble Single-Walled Carbon Nanotubes after a Significant Degree of Sidewall Functionalization by the Bingel Reaction
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- 作者：Tomokazu Umeyama ; Noriyasu Tezuka ; Mitsuru Fujita ; Yoshihiro Matano ; Norihiko Takeda ; Kei Murakoshi ; Kaname Yoshida ; Seiji Isoda ; Hiroshi Imahori
- 刊名：Journal of Physical Chemistry C
- 出版年：2007
- 出版时间：July 12, 2007
- 年：2007
- 卷：111
- 期：27
- 页码：9734 - 9741
- 全文大小：273K
- 年卷期：v.111,no.27(July 12, 2007)
- ISSN：1932-7455
文摘
Sidewalls of acid-treated, shortened single-walled carbon nanotubes (SWNTs) with long alkyl chains at theopen ends and defect sites have been functionalized by Bingel reaction to examine the structures andspectroscopic properties in detail for the first time. The microwave-assisted Bingel reaction has been successfullyapplied to the sidewall functionalization of which the reaction rate is ca. 50 times faster than that under theconventional conditions. The degree of the sidewall functionalization (one diester unit per 75-300 carbonatoms of SWNTs) was found to be controllable by changing the output power of the microwave under thesame temperature. Atomic force microscopy and transmission electron microscopy showed the progressiveexfoliation of the SWNT bundles by the double chemical modification. Resonant Raman and UV-vis-NIRabsorption spectroscopies revealed that the electronic properties of SWNT are largely retained after a significantdegree of sidewall modification by the Bingel reaction without apparent selective reactivity for metallic andsemiconducting SWNTs. This is in remarkable contrast with the conventional sidewall functionalization ofSWNTs leading to the loss of their electronic properties (one functional group per 10-100 carbon atoms onthe sidewall). Thus, our covalent functionalization methodology can provide SWNT materials with bothexcellent solubility and inherent electronic properties which are highly desirable in solution-phase processingfor the fabrication of SWNT-based molecular devices.