Abstract
<jats:p>While ubiquitous in nature, synthetic nanostructures that form ring- or spiral-like structures have remained particularly elusive. This has been especially the case for all-inorganic systems, which despite their potential to manifest distinct long-range physical states arising from twisting and inversion symmetry breaking, are generally devoid of twist-inducing interactions such as hydrogen bonding, πstacking, and disulfide bridging. Here, leveraging the non-covalently bound and one-dimensional (1D) 20 van der Waals (vdW) nature of transition metal trichalcogenides, we demonstrate the compositionally driven formation of well-defined spiral nanorings from NbS3 Type I (NbS3-I) chains that spontaneously self-coil through deliberate Ta alloying and S vacancy formation, forming Nb1-xTaxS3-d during vaporphase crystallization. The spiraled nanorings displayed an average circumference of 17 ± 4 µm, with average cross-sectional heights from ~550 nm down to ~20 nm, and widths ~620 nm down to ~40 nm, 25 respectively. We reconcile the compositionally driven spiraling of the chains into nanorings using density functional theory (DFT) calculations on idealized model structures, which revealed that Ta incorporation disrupts the intra-chain Nb–Nb dimerization, weakens the inter-chain bonding, lowers the Young’s modulus by a factor of ~5.6 relative to pristine NbS3-I, and renders the chains more susceptible to spiraling and self-coiling into nanorings during vapor-phase growth. Owing to their high refractive index and 30 nanoscale dimensions, these nanorings exhibit strong optical activity and size-dependent dipolar photonic signatures reminiscent of confined Mie-type resonance. Their nanoring geometry and structural anisotropy further give rise to polarization-dependent light scattering. These findings establish a deliberate and predictable synthetic route to access atypical nanoscale ring morphologies in 1D vdW solids, highlighting the potential of programmed spiraling and twisting of extended lattice nanostructures to realize optically 35 active nanoscale platforms and collective states arising from curved and twisted structures.</jats:p>