UC Irvine

One-dimensional (1D) van der Waals (vdW) materials provide a unique platform that enables the understanding of how anisotropic bonding governs crystal growth and enables access to complex morphologies and emergent physical states. However, predictive synthetic strategies for directing their crystallization remain underdeveloped. This work establishes chemical design principles for directing the bottom-up crystallization of 1D vdW materials by controlling directional bonding, composition, and defect-mediated growth. Using modified chemical vapor transport, strong intrachain bonding—particularly Peierls-like metal dimerization—is shown to promote catalyst-free growth of ultralong, high-aspect-ratio nanowires in NbS3-I and MoI3. Building on this framework, compositional alloying and chalcogen deficiency emerge as complementary chemical design parameters that modify lattice flexibility and growth pathways that enable the formation of selfcoiled nanorings and screw-dislocation-mediated spiral hillocks while preserving the intrinsic anisotropic properties of the parent crystals. Microscopy, spectroscopy, and first-principles calculations collectively reveal the interplay between bonding anisotropy, lattice perturbations, and crystal growth. Together, these studies establish generalizable chemical design principles for programming crystal growth in burgeoning classes of 1D vdW materials and provide new synthetic routes to structurally complex crystals that serve as platforms for exploring structure–property relationships and emergent physical phenomena.