Xu Ziwei, Qiu Lu, Ding Feng
Institute of Textiles and Clothing , Hong Kong Polytechnic University , Hong Kong S.A.R. , China.
School of Materials Science & Engineering , Jiangsu University , Zhenjiang 212013 , China.
Chem Sci. 2018 Feb 19;9(11):3056-3061. doi: 10.1039/c7sc04714b. eCollection 2018 Mar 21.
Depending on its specific structure, or so-called chirality, a single-walled carbon nanotube (SWCNT) can be either a conductor or a semiconductor. This feature ensures great potential for building ∼1 nm sized electronics if chirality-selected SWCNTs could be achieved. However, due to the limited understanding of the growth mechanism of SWCNTs, reliable methods for chirality-selected SWCNTs are still pending. Here we present a theoretical model on the chirality assignment and control of SWCNTs during the catalytic growth. This study reveals that the chirality of a SWCNT is determined by the kinetic incorporation of pentagons, especially the last (6) one, during the nucleation stage. Our analysis showed that the chirality of a SWCNT is randomly assigned on a liquid or liquid-like catalyst surface, and two routes of synthesizing chirality-selected SWCNTs, which are verified by recent experimental achievements, are demonstrated. They are (i) by using high melting point crystalline catalysts, such as Ta, W, Re, Os, or their alloys, and (ii) by frequently changing the chirality of SWCNTs during their growth. This study paves the way for achieving chirality-selective SWCNT growth for high performance SWCNT based electronics.
取决于其特定结构，即所谓的手性，单壁碳纳米管（SWCNT）可以是导体或半导体。如果能够实现手性选择的单壁碳纳米管，这一特性确保了构建约1纳米尺寸电子器件的巨大潜力。然而，由于对单壁碳纳米管生长机制的理解有限，用于手性选择单壁碳纳米管的可靠方法仍未出现。在此，我们提出了一个关于催化生长过程中单壁碳纳米管手性分配和控制的理论模型。这项研究表明，单壁碳纳米管的手性是由五边形在成核阶段的动力学掺入决定的，特别是最后一个（第6个）五边形。我们的分析表明，单壁碳纳米管的手性在液体或类液体催化剂表面是随机分配的，并且展示了两种合成手性选择单壁碳纳米管的途径，这已得到近期实验成果的验证。它们是：（i）使用高熔点晶体催化剂，如钽、钨、铼、锇或它们的合金；（ii）在单壁碳纳米管生长过程中频繁改变其手性。这项研究为实现用于高性能基于单壁碳纳米管的电子器件的手性选择性单壁碳纳米管生长铺平了道路。
