External field-assisted nanoscale 3D printing: From mechanisms to applications

Abstract

The development of next-generation multi-functional devices demands manufacturing approaches that combine nanoscale resolution, geometric freedom, material versatility, and scalability. Nanoscale 3D printing (3DNP) holds promise for fabricating complex 3D architectures with designer composition and functionality, yet standard 3D printing techniques face hardware and mechanistic limits that constrain resolution, throughput, cost, and material compatibility. The integration of external fields with advanced 3D additive manufacturing methods provides additional control over material deposition and local properties at the sub-micrometer scale. This Review provides a systematic overview of external field-assisted 3DNP, bridging the gap from fundamental mechanisms to emerging device applications. We first classify the printable building blocks, including nanoparticle-based inks and precursor/ion solutions, and analyze their dispersion stability for allowable interactions with specific fields. We then show recent progresses in 3DNP and quantitatively describe how different fields act as programmable handles on the printing process, covering the manipulation of voxels via electric fields, the regulation of evaporation kinetics through flow fields, the induction and transform of chemical bonding by optical and thermal fields, the re-assembly and resolution refinement with a sacrificial phase-change field, and the redox deposition and surface modification by chemical potential fields. Furthermore, the Review highlights 3DNP device applications that are difficult to realize with conventional techniques, including advances in scalable parallelized printing and multi-material integration for functional micro-nano devices. Finally, we identify current challenges and offer an outlook on the development of a general nanomanufacturing platform for high-precision, multi-component integrated devices.