[17a-C303-1~8] 17.1 Carbon nanotubes & other nanocarbon materials

[17a-C303-1] Digital isotope labeling for tracing growth histories of individual CNTs

〇Shun Yamamoto¹, Keigo Otsuka¹, Taiki Inoue¹, Rong Xiang¹, Shohei Chiashi¹, Shigeo Maruyama^1,2 (1.Tokyo Univ., 2.AIST)

Keywords:cabon nanotube, growth mechanism, isotope label

We will present report a digital isotope coding technique to trace the growth behavior of individual single-walled carbon nanotubes (SWNTs). Recent progresses on the structure-controlled synthesis attracted renewed attentions; thermodynamic and kinetic control of the nanotube growth led to high-density arrays of chirality-selected SWNTs. Some experimental and theoretical studies support such a controllability, but it is still controversial, for example, whether the growth rate depends on tube chirality. This is because breakdown of the length of individual SWNTs into growth rate, incubation and lifetime is still challenging especially for application-oriented synthesis. The presented method directly can answers such questions by drawing growth curves for numerous SWNTs on single chips, from nucleation to catalyst death. Simple example of our method showed that most of SWNTs elongated at constant rates until abrupt termination, while the catalysts remained at original position (so-called base-growth mode). Ex situ detection of isotope codes by Raman enabled not only a comparison among numerous SWNTs but also the growth analysis for unusual SWNTs with multiple chiralities. Digital isotope coding also offered the direct link between modulation of growth conditions and corresponding changes in growth behavior along identical SWNTs. We expect that applying this technique to a variety of catalysts and conditions, in combination with atomic-scale simulation and microscopy, will offer a lot of clues to the mechanism of SWNT growth, and accelerate the control of chirality and morphology toward high-end applications.