Optical evaluation of the metal-to-semiconductor ratio of single-wall carbon nanotubes
Optical evaluation of the metal-to-semiconductor ratio of single-wall carbon nanotubes
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DOI：
10.1021/jp804006f
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发表时间：
2008-08-28
影响因子：
3.7
通讯作者：
Kataura, Hiromichi
中科院分区：
文献类型：
--
作者：
Miyata, Yasumitsu;Yanagi, Kazuhiro;Kataura, Hiromichi
利用光学吸收光谱研究了激光烧蚀法制备的单壁碳纳米管（SWCNTs）的金属-半导体比。使用密度梯度离心法将SWCNTs分离成金属和半导体。测量了两种单壁碳纳米管从近红外到紫外的吸收光谱。一个简单的叠加分析表明，原始的单壁碳纳米管由27 +/- 3%的金属单壁碳纳米管和73 3%的半导体单壁碳纳米管，而不使用理论校正。从详细的振荡器拟合，发现金属SWCNT M（11）的第一激子跃迁的吸收系数与半导体SWCNT S（1 r）的第一激子跃迁的吸收系数几乎相同，直径分布为1.1，类似于1.3 nm。这一结果提供了一个简单的光学评价方法，以估计由不同的方法产生的各种单壁碳纳米管样品的金属-半导体比。
The metal-to-semi conductor ratio for single-wall carbon nanotubes (SWCNTs) produced by laser ablation was investigated using optical absorption spectroscopy. The SWCNTs were separated into metals and semiconductors using the density gradient centrifugation method. The optical absorption spectra of both SWCNTs were measured from the near-infrared to ultraviolet. A simple superposition analysis revealed that the pristine SWCNTs consist of 27 +/- 3% metallic SWCNTs and 73 3% semiconducting SWCNTs without using a theoretical Correction. From the detailed oscillator fitting, it was found the absorption coefficient of the first excitonic transition of metallic SWCNTs M(11) was almost the same as that of semiconducting SWCNTs S(1r) for a diameter distribution of 1.1 similar to 1.3 nm. This result provides a simple optical evaluation method to estimate the metal-to-semiconductor ratio of various SWCNT samples produced by different methods.