Department of Mechanical Engineering , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku , Tokyo 113-8656 , Japan.
Energy NanoEngineering Laboratory , National Institute of Advanced Industrial Science and Technology (AIST) , 1-2-1 Namiki , Tsukuba 305-8564 , Japan.
ACS Nano. 2018 Apr 24;12(4):3994-4001. doi: 10.1021/acsnano.8b01630. Epub 2018 Apr 9.
Single-walled carbon nanotubes (SWCNTs) are attracting increasing attention as an ideal material for high-performance electronics through the preparation of arrays of purely semiconducting SWCNTs. Despite significant progress in the controlled synthesis of SWCNTs, their growth mechanism remains unclear due to difficulties in analyzing the time-resolved growth of individual SWCNTs under practical growth conditions. Here we present a method for tracing the diverse growth profiles of individual SWCNTs by embedding digitally coded isotope labels. Raman mapping showed that, after various incubation times, SWCNTs elongated monotonically until their abrupt termination. Ex situ analysis offered an opportunity to capture rare chirality changes along the SWCNTs, which resulted in sudden acceleration/deceleration of the growth rate. Dependence on growth parameters, such as temperature and carbon concentration, was also traced along individual SWCNTs, which could provide clues to chirality control. Systematic growth studies with a variety of catalysts and conditions, which combine the presented method with other characterization techniques, will lead to further understanding and control of chirality, length, and density of SWCNTs.
单壁碳纳米管 (SWCNTs) 作为高性能电子学的理想材料引起了越来越多的关注，通过制备纯半导体 SWCNTs 的阵列来实现。尽管在 SWCNTs 的可控合成方面取得了重大进展，但由于难以分析实际生长条件下单个 SWCNTs 的时变生长，其生长机制仍不清楚。在这里，我们提出了一种通过嵌入数字编码同位素标记来追踪单个 SWCNTs 不同生长轮廓的方法。拉曼映射表明，在不同的孵育时间后，SWCNTs 单调伸长，直到突然终止。原位分析提供了捕获 SWCNTs 上罕见手性变化的机会，这导致了生长速率的突然加速/减速。对依赖于生长参数（如温度和碳浓度）的追踪也是沿着单个 SWCNTs 进行的，这可以为手性控制提供线索。通过使用各种催化剂和条件进行系统的生长研究，将本文提出的方法与其他表征技术相结合，将有助于进一步理解和控制 SWCNTs 的手性、长度和密度。
