Since the discovery of fullerenes in 1985, nanocarbon materials have played a crucial role in materials science. Over the past decade, significant efforts have been directed towards exploring post nanocarbons. Two-dimensional (2D) layers of transition metal chalcogenides (TMCs) have been widely recognized as ‘beyond graphene’ due to their versatile chemistry. On the other hand, their 1D counterparts (nanowires, nanoribbons, and nanotubes) could exhibit the unique electronic properties, significantly distinct from the 2D layers as well as 1D nanocarbons (Fig. 1a).^[1] However, exploring their potentials has been hampered by their limited availability. Although these materials have been prepared by using chemical and lithographic methods,^[2] the reliable production of well-defined 1D TMCs remains a significant challenge.

Here we report atomically precise fabrication of 1D TMCs by using carbon/boron-nitride nanotubes (CNTs/BNNTs) as a template. Chemically and mechanically robust CNTs/BNNTs have increasingly been employed to promote and stabilize the bottom-up growth of 1D materials, allowing their facile handling and characterization. Isolation of a single MoTe/WTe nanowires inside CNTs enabled us to observe their dynamic torsions, which are not seen in the bulk (Fig. 1b).^[3] Furthermore, we have utilized hollow spaces and external surfaces of BNNTs to produce a variety of 1D MX₂ structures including single-walled MoS₂NTs with the small diameter of ~1 nm. Electrically and optically insulating BNNTs can serve as an ideal ‘nano-test-tubes’ for precisely studying electronic properties of guest materials. The successful syntheses of 1D TMCs using CNTs/BNNTs might open up the possibilities for exploring unprecedented physics and potential applications.

Reference:

[1] a) G. Seifert et al. Phys. Rev. Lett. 1999, 85, 146. b) Y. Li et al. J. Am. Chem. Soc. 2008, 130, 16739. c) I. Popov et al. Nano Lett. 2008, 8, 4093. [2] (a) J. Kibsgaard et al. Nano Lett. 2008, 8, 3928. (b) X. Liu et al. Nat. Commun. 2013, 4, 1776. (c) P. Chithaiah et al. ACS Nano 2020, 14, 3004 [3] (a) M. Nagata et al. Nano Lett. 2019, 19, 4845. (b) N. Kanda et al. Nanoscale 2020, 12, 17185.