Researchers have developed a microfabrication technique that assembles atomically precise metal nanoclusters into three-dimensional architectures while cutting electrical resistivity by three orders of magnitude, according to research published in Nature Communications.
The technique uses nitrene-mediated two-photon lithography guided by physical rheology. By tracking the geometric ratio between nanocluster cores and their organic ligands, the researchers identified a deterministic transition from rigid solids to viscoelastic liquids. Molecular dynamics simulations and rheological testing confirmed that high free volume within the viscoelastic liquid state enables covalent crosslinking, whereas solid-like states remain jammed and cause poor printability.
The printed architectures retain the semiconducting characteristics of the original metal cores. Scaling atomically precise metal nanoclusters into functional macroscopic hardware has previously faced manufacturing barriers, as standard processing damaged fragile quantum structures and lacked physical metrics to predict whether nanocluster materials could be printed consistently.
Shiyu Ji and Wanyu Shen contributed equally as lead authors on the paper. The team performed AI-driven experiments, simulations, and model training on the robotic AI-Scientist platform of the Chinese Academy of Sciences. Authors on the project represented institutions including the University of Science and Technology of China, Tsinghua University, the CAS Institute of Solid State Physics, and Donghua University.
The researchers evaluated two-dimensional patterns, three-dimensional structures, and free volume energy optimization across systems including Au25 and Au38 clusters paired with C4 and C12 ligands. The study was supported by the National Natural Science Foundation of China, the Anhui Provincial Natural Science Foundation, the China Postdoctoral Science Foundation, and the Beijing Natural Science Foundation.
