Structural Diversity of Single‐Walled Transition Metal Dichalcogenide Nanotubes Grown via Template Reaction

Abstract

Monolayers of transition metal dichalcogenides (TMDs) are an ideal 2D platform for studying a wide variety of electronic properties and potential applications due to their chemical diversity. Similarly, single‐walled TMD nanotubes (SW‐TMDNTs)—seamless cylinders of rolled‐up TMD monolayers—are 1D materials that can exhibit tunable electronic properties depending on both their chirality and composition. However, much less has been explored about their geometrical structures and chemical variations due to their instability under ambient conditions. Here, the structural diversity of SW‐TMDNTs templated by boron nitride nanotubes (BNNTs) is reported. The outer surfaces and inner cavities of the BNNTs promote and stabilize the coaxial growth of SW‐TMDNTs with various diameters, including few‐nanometers‐wide species. The chiral indices (n,m) of individual SW‐MoS2NTs are assigned by high‐resolution transmission electron microscopy, and statistical analyses reveals a broad chirality distribution ranging from zigzag to armchair configurations. Furthermore, this methodology can be applied to the synthesis of various TMDNTs, such as selenides and alloyed Mo1−xWxS2. Comprehensive microscopic and spectroscopic analyses also suggest the partial formation of Janus MoS2(1−x)Se2x nanotubes. The BNNT‐templated reaction provides a universal platform to characterize the chirality‐dependent properties of 1D nanotubes with various electronic structures.

Nanoscrolls of Janus Monolayer Transition Metal Dichalcogenides

“…The difference in structural and electronic properties between nanotubes and nanoscrolls is worth noting. So far, TMDC nanotubes with small diameters have been studied theoretically , and recently synthesized around/inside carbon (or boron nitride) nanotubes. ,, Unlike nanotubes, nanoscrolls have nonclosed sheet structures and edges. Although the DFT calculations of nanoscrolls are difficult, we consider that these two structures have similar band structures, because the edge effect in nanoscrolls should be minor.…”

Interlayer Charge Transfer Induced Electrical Behavior Transition in 1D AgI@sSWCNT van der Waals Heterostructures

“…However, it should be pointed out that, due to the strong strain effect caused by the curved surface, the growth efficiency and the diameter of the grown nanotube have been greatly limited. 16,17 Meanwhile, a variety of 1D vdWHs have been prepared by filling materials into the 1D cavity of nanotubes, 18 including molecules, 19−22 elements, 23−25 halides, 26−31 chalcogenides, 32−35 transition metal carbides, 36 and perovskites. 37,38 However, the low synthesis efficiency of 1D vdWHs materials and the fact that carbon nanotubes contain both semiconducting and metallic types 39,40 increase the difficulty of electrical study in 1D vdWHs.…”

“…The coating method, which means attachment to the outer surface of a 1D material by vdW interaction, has been successfully used to obtain BN and MoS 2 nanotubes on the surface of single-walled carbon nanotubes (SWCNTs). However, it should be pointed out that, due to the strong strain effect caused by the curved surface, the growth efficiency and the diameter of the grown nanotube have been greatly limited. , Meanwhile, a variety of 1D vdWHs have been prepared by filling materials into the 1D cavity of nanotubes, including molecules, − elements, − halides, − chalcogenides, − transition metal carbides, and perovskites. , However, the low synthesis efficiency of 1D vdWHs materials and the fact that carbon nanotubes contain both semiconducting and metallic types , increase the difficulty of electrical study in 1D vdWHs. There has been little research on the electrical behavior and interlayer interaction of 1D vdWHs.…”

Semiconducting Transition Metal Dichalcogenide Heteronanotubes with Controlled Outer-Wall Structures

“…We discuss the comparison of this study to previous studies. In the previous studies, structure-controlled heteronanotubes based on carbon nanotubes or boron nitride nanotubes were synthesized using the CVD method. − In those approaches, due to the presence of metallic carbon nanotubes or the insulating nature of boron nitride nanotubes, there are still challenges in forming pure semiconducting nanotubes, i.e., pure semiconductor–semiconductor heterojunctions, which have unique optical properties and potential applications. − On the contrary, TMDC nanotubes exhibit semiconducting properties regardless of their structure, , and their heteronanotubes have advantages in forming semiconductor–semiconductor heterojunctions. In this study, using the chalcogenization method, we demonstrated the production of semiconducting heteronanotubes with controlled structures such as layer number and crystallinity as well as the production of semiconducting heteronanotubes with specific chirality.…”