Preparation of single-walled carbon nanotubes (SWNTs) with diameters ranging from 1.2 to 1.5 nm has been highly demanded for field-effect transistors with superior properties. In the work, we report the chemical vapor deposition synthesis of SWNTs with an average diameter of 1.2 nm from a rationally designed nickel catalyst supported by magnesia. The high metal dispersion, the suitable reaction temperature, and the use of a methane carbon source co-determine the SWNT diameter distribution. Furthermore, through the synergistic application of poly(9,9-dioctylfluorene-2,7-diylalt-pyridine-2,6-diyl) wrapping and ultracentrifugation, SWNTs with enriched (10,8) species of 1.24 nm are successfully extracted, which is attributed to the selective interaction between the polymer molecules and the targeted SWNTs. This work not only sheds light on the growth of SWNTs with relatively large diameter, but also paves the way towards the preparation of high purity (n,m) species that could meet the requirements of advanced high-tech applications.

中文翻译：

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平均直径1.2 nm单壁碳纳米管的制备

为了获得具有优异性能的场效应晶体管，人们对直径范围为1.2至1.5 nm的单壁碳纳米管（SWNT）的制备有着强烈的需求。在工作中，我们报道了通过合理设计的氧化镁负载的镍催化剂化学气相沉积合成平均直径为1.2 nm的SWNT。高金属分散度、合适的反应温度和甲烷碳源的使用共同决定了单壁碳纳米管的直径分布。此外，通过聚(9,9-二辛基芴-2,7-二基吡啶-2,6-二基)包裹和超速离心的协同应用，成功提取了1.24 nm的富集(10,8)物质的单壁碳纳米管，其这归因于聚合物分子和目标单壁碳纳米管之间的选择性相互作用。这项工作不仅揭示了相对较大直径的单壁碳纳米管的生长，而且为制备满足先进高科技应用要求的高纯度（n，m）物种铺平了道路。