Viscoelasticity-guided covalent assembly of atomically precise nanoclusters via nitrene-mediated two-photon lithography

Abstract

The translation of atomically precise metal nanoclusters into functional macroscopic devices is restricted by the difficulty of scaling manufacturing while preserving fragile quantum structures. Although two-photon lithography offers a route for micro-fabrication, the absence of definitive physical criteria to predict “printability” results in inconsistent fabrication outcomes. Here we report a fabrication strategy that utilizes rheology as a predictive descriptor to guide the high-fidelity, covalent assembly of nanoclusters into arbitrary architectures. We identify a rheological state transition from rigid solids to viscoelastic liquids, which is deterministically governed by the core-to-ligand geometric ratio. By employing rheological tests and molecular dynamics simulations, we demonstrate that high free volume in liquid states facilitates crosslinking. In contrast, solid-like states remain jammed and suffer from poor printability. The resulting architectures preserve the semiconducting nature of the cores while exhibiting electrical resistivity three orders of magnitude lower than their single-crystal counterparts. This physics-guided framework bridges the gap between atomic precision and macroscopic materials engineering, providing a foundation for superatomic quantum electronics. Atomically precise nanoclusters are difficult to shape into functional devices. Here, the authors exploit their viscoelastic flow properties to guide the laser printing of 3D structures that offer semiconducting behavior and improved charge transport.