Giant Raman Response to the Encapsulation of Sulfur in Narrow Diameter Single-Walled Carbon Nanotubes

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• 作者：Guanghui Li ; Chengyin Fu ; M. Belén Oviedo ; Mingguang Chen ; Xiaojuan Tian ; Elena Bekyarova ; Mikhail E. Itkis ; Bryan M. Wong ; Juchen Guo ; Robert C. Haddon
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：138
• 期：1
• 页码：40-43
• 全文大小：300K
• ISSN：1520-5126

文摘

Encapsulation of sulfur in HiPCO-SWNTs leads to large changes in the Raman spectra with the appearance of new peaks at 319, 395, and 715 cm^–1 which originate from the sulfur species within the SWNTs, while the high frequency SWNT bands (ν > 1200 cm^–1) are decreased in intensity. The encapsulated species also shifts the near-IR interband electronic transitions to lower energy by more than 10%. These effects seem to originate with the van der Waals interaction of the confined sulfur species with the walls of the SWNTs which are not expected to be significant in the case of the previously studied large diameter SWNTs. We suggest that sulfur in the small diameter SWNTs exists as a helical polymeric sulfur chain that enters the SWNT interior in the form of S₂ (³Σ_g^–) molecules which undergo polymerization to linear diradicals.