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Synthesis of nitrogen-doped single-walled carbon nanotubes and monitoring of doping by Raman spectroscopy 下载免费PDF全文
Nitrogen-doped single-walled carbon nanotubes (CNx-SWNTs) with tunable dopant concentrations were synthesized by chemical vapor deposition (CVD), and their structure and elemental composition were characterized by using transmission electron microscopy (TEM) in combination with electron energy loss spectroscopy (EELS). By comparing the Raman spectra of pristine and doped nanotubes, we observed the doping-induced Raman G band phonon stiffening and 2D band phonon softening, both of which reflect doping-induced renormalization of the electron and phonon energies in the nan- otubes and behave as expected in accord with the n-type doping effect. On the basis of first principles calculations of the distribution of delocalized carrier density in both the pristine and doped nanotubes, we show how the n-type doping occurs when nitrogen heteroatoms are substitutionally incorporated into the honeycomb tube-shell carbon lattice. 相似文献
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以柠糠酸酐为原料, 合成了一种可以与丙烯腈(AN, acrylonitrile)共聚的新单体: 2-甲基-2-丁烯二酸单甲酯(MBAME). 以偶氮二异丁腈(AIBN, 2,2’-azobis isobutyronitrile)为引发剂, 70 ℃下引发MBAME与AN在N,N-二甲基甲酰胺(DMF, N,N-dimethylformamide)中进行无规共聚, 通过Fineman-Ross法测定了两者在DMF溶液聚合体系的表观竞聚率, γ1(AN)=7.985, γ2(MBAME)=0.599, 有助于优化聚丙烯腈基碳纤维用树脂的生产工艺. 相似文献
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粘胶基碳纤维表面结构的STM研究 总被引:1,自引:0,他引:1
本文建立了用具有原子级分辨能力的扫描隧道显微镜 (STM)研究粘胶基碳纤维 (RCF)表面结构的方法。在较大尺度的STM图像上 ,RCF表面显得很粗糙 ,“峰”和“谷”的特征非常明显。增大放大率时 ,发现了约10nm宽的条状结构 ,其排列与纤维轴成一定角度 (45°~ 90°)。首次获得了RCF原子级的STM图像 ,在原子级尺度上 ,其原子排列并不规则 ,相邻原子间距为 0 .14 2nm ,最近六元环中心的距离是 0 .2 5 3nm。与高定向降解石墨 (HOPG)的对比研究进一步表明RCF表面的碳网是变形的六元环结构 相似文献
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