Doping single-walled carbon nanotubes with surfactant peptides containing electron-donor substituents and nitrogen heterocycles
Doping single-walled carbon nanotubes with surfactant peptides containing electron-donor substituents and nitrogen heterocycles
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DOI：
10.1016/j.carbon.2013.01.039
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发表时间：
2013-06
期刊：
影响因子：
10.9
通讯作者：
D. Samarajeewa;G. Dieckmann;S. Nielsen;I. Musselman
中科院分区：
文献类型：
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作者：
D. Samarajeewa;G. Dieckmann;S. Nielsen;I. Musselman
我们研究了一系列具有不同供电子能力的芳香族基团改变单壁碳纳米管电子性质的潜力。选择的芳香族部分包括对氨基苯丙氨酸、3-[4-（二甲基氨基）苯基]丙酸、酪氨酸、色氨酸和4-吡啶基丙氨酸。这些部分含有环外电子供体取代基，如胺、二甲胺和羟基，以及含氮杂环，包括吲哚和吡啶。我们将这些芳香族分子连接到两亲性表面活性剂肽的N-末端，并获得稳定的水性肽/单壁碳纳米管分散体。原子力显微镜图像和紫外-可见-近红外光谱显示，在所使用的条件下，所有的肽，除了与4-吡啶基丙氨酸，分散单壁碳纳米管以及在溶液中。局部电子态密度的肽涂层单壁碳纳米管进行了检查，使用扫描隧道光谱dI/dV图。所有的光谱显示在导带侧非常接近费米能级的额外的峰，表明单壁碳纳米管的n型掺杂。通过拉曼光谱G带峰下移进一步验证了掺杂行为。此外，我们发现杂原子的位置对芳香族部分和SWCNT之间的相互作用有显著贡献。
We examined the potential of a series of aromatic moieties with different electron-donating ability to alter SWCNT electronic properties. The selected aromatic moieties included p-amino-phenylalanine, 3-[4-(dimethylamino)phenyl]propanoic acid, tyrosine, tryptophan, and 4-pyridylalanine. These moieties contained exocyclic electron-donor substituents, such as amine, dimethylamine, and hydroxyl groups, as well as nitrogen-containing heterocycles, including indole and pyridine. We attached these aromatic molecules to the N-terminus of an amphiphilic surfactant peptide and obtained stable aqueous peptide/SWCNT dispersions. Atomic force microscopy images and ultraviolet–visible–near-infrared spectra revealed that, under the conditions used, all peptides, except for the one with 4-pyridylalanine, disperse SWCNTs well in solution. The local electron density of states of the peptide-coated SWCNTs was examined using scanning tunneling spectroscopy dI/dV plots. All spectra showed an additional peak in the conduction band side very close to the Fermi level, indicating n-type doping of the SWCNTs. The doping behavior was further verified by Raman spectroscopy G-band peak downshifts. Additionally, we found that the location of the heteroatom contributes significantly to the interaction between the aromatic moieties and the SWCNTs.