Single-Chirality Separation and Optical Properties of (5,4) Single-Wall Carbon Nanotubes

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• 作者：Xiaojun Wei ; Takeshi Tanaka ; Naoto Akizuki ; Yuhei Miyauchi ; Kazunari Matsuda ; Mari Ohfuchi ; Hiromichi Kataura
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：May 19, 2016
• 年：2016
• 卷：120
• 期：19
• 页码：10705-10710
• 全文大小：419K
• 年卷期：0
• ISSN：1932-7455

文摘

In this study, high-purity single-chirality (5,4) and (6,4) single-wall carbon nanotubes (SWCNTs) were efficiently extracted using gel chromatography, and their optical properties were investigated. In the photoluminescence spectrum, the (5,4) SWCNTs exhibited multiple emission peaks, such as E₁₁^* at 968 and E₁₁^*− at 1096 nm, in addition to the original E₁₁ peak at 829 nm for the E₂₂ excitation. Although the (6,4) SWCNTs also exhibited similar emission peaks, the intensity of the additional peaks relative to the E₁₁ peak was approximately four times lower than that of (5,4) SWCNTs, even though the same separation procedure was used for both species. The results from density functional theory calculations indicated that both the E₁₁^* and E₁₁^*− emissions originated as emissions from the oxide states. Because no oxidation treatments were performed on the samples, these oxides were most likely spontaneously produced during the sample preparation process. Theoretical results indicated that the (5,4) SWCNT possesses a more stable ether-a-O structure that could cause the E₁₁^* emission. The difference in the stability of the oxide states for (5,4) SWCNT and (6,4) SWCNT strongly suggests that the (5,4) SWCNT is more likely to be oxidized by weak stimulation. These results indicate that the (5,4) SWCNT remained near the outside of the robust structure due to its strong curvature effects.