Bonding-Directed Crystallization of Ultra-Long One-Dimensional NbS van der Waals Nanowires.

The rediscovery of one-dimensional (1D) and quasi-1D (q-1D) van der Waals (vdW) crystals ushered the realization of nascent physical properties in 1D that are suitable for applications in photonics, electronics, and sensing. However, despite renewed interest in the creation and understanding of the physical properties of 1D and q-1D vdW crystals, the lack of accessible synthetic pathways for growing well-defined nanostructures that extend across several length scales remains. Using the highly anisotropic 1D vdW NbS-I crystal as a model phase, we present a catalyst-free and bottom-up synthetic approach to access ultralong nanowires, with lengths reaching up to 7.9 mm and with uniform thicknesses ranging from 13 to 160 nm between individual nanowires. Control over the synthetic parameters enabled the modulation of intra- and interchain growth modalities to selectively yield only 1D nanowires or quasi-2D nanoribbons. Comparative synthetic and density functional theory (DFT) studies with a closely related nondimerized phase, ZrS, show that the unusual preferential growth along 1D can be correlated to the strongly anisotropic bonding and dimeric nature of NbS-I.