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Liquid-phase exfoliation (LPE) of emergent materials composed of weakly bound one-dimensional (1D) and quasi-1D (q-1D) building blocks presents a straightforward route not only for the discovery of confined physical states in 1D but also for the realization of scalable functional devices. However, compared to the more established routes in two-dimensional (2D) crystals, the nature of LPE in 1D and q-1D crystals presents a more random process. This distinction arises from the various available interchain directions across several crystallographic facets unique to 1D and q1D solids, from which the chains can be cleaved apart into a stochastic combination of nanowires, nanoribbons, and nanosheets. Using the 1D ionic phase comprised of ∼4.3 Å thin chains, (NbSe4)3I, we demonstrate herein the profound influence of crystal morphology, exposed facets, and their degree of wettability, passivation, and surface roughness in directing the LPE behavior of 1D crystals. Through the growth of bulk crystals as long needles with exposed (hk0) facets or as quasi-2D flakes with exposed (00l) facets susceptible to passivation, we show that these two distinct precursor morphologies display divergent behaviorboth in solvent preference and quality of resulting nanostructures. Under optimal conditions involving bulk needles and tetrahydrofuran as solvent, we show that the LPE of (NbSe4)3I results in ultrathin nanoribbons with high aspect ratios bearing lengths >5 μm, thicknesses down to 7.2 ± 2.6 nm, and widths of 26.4 ± 10.9 nm. The nanoribbons, solution processable as thin films, retain their native crystal structure and semiconducting character. Moreover, the nanoribbons also manifest pronounced degrees of bending and substrate-driven twisting at the nanoscale while maintaining long-range order. These results highlight a means to understand the fundamental chemical and physical behavior of noncovalently bound 1D solids through the realization of solution-processable 1D nanoribbons and nanowires that also have the potential as components for next-generation devices that approach the atomic scale. 

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 NbS3–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, ZrS3, show that the unusual preferential growth along 1D can be correlated to the strongly anisotropic bonding and dimeric nature of NbS3–I. 

Metallic charge transport and porosity appear almost mutually exclusive. Whereas metals demand large numbers of free carriers and must have minimal impurities and lattice vibrations to avoid charge scattering, the voids in porous materials limit the carrier concentration, provide ample space for impurities, and create more charge-scattering vibrations due to the size and flexibility of the lattice. No microporous material has been conclusively shown to behave as a metal. Here, we demonstrate that single crystals of the porous metal–organic framework Ln 1.5 (2,3,6,7,10,11-hexaoxytriphenylene) (Ln = La, Nd) are metallic. The materials display the highest room-temperature conductivities of all porous materials, reaching values above 1,000 S/cm. Single crystals of the compounds additionally show clear temperature-deactivated charge transport, a hallmark of a metallic material. Lastly, a structural transition consistent with charge density wave ordering, present only in metals and rare in any materials, provides additional conclusive proof of the metallic nature of the materials. Our results provide an example of a metal with porosity intrinsic to its structure. We anticipate that the combination of porosity and chemical tunability that these materials possess will provide a unique handle toward controlling the unconventional states that lie within them, such as charge density waves that we observed, or perhaps superconductivity.