Photocatalytic Reduction for Integrated Single-vat Multimaterial 3D Printing

Abstract Photocatalysis is introduced as a viable chemical scheme in vat photopolymerization additive manufacturing (AM). Specifically, we demonstrate the use of acridinium photocatalysts to facilitate reduction of silver salts toward the patterned formation of conductive silver wires. Electronic devices are typically manufactured by fabricating and assembling electrically distinct materials, a multistep approach that requires various feedstocks, energy-intensive processing, and complex workflows. Here, we introduce a chemistry-driven strategy for multimaterial AM, coined Photocatalytic Reduction for Integrated Single-vat Multimaterial 3D Printing (PRISM 3DP), in which conductive and insulating materials are synthesized directly from a single homogeneous liquid precursor. Wavelength-selective photocatalysis enables visible light to reduce metal salts and generate conductive metal pathways in situ, whereas ultraviolet light initiates acrylate polymerization to form dielectric, insulating polymer domains. Automated high-throughput photochemical screening identified resin formulations that promoted nanoparticle formation while maintaining favorable photopolymerization behavior. The resulting polymer domains exhibit an average dielectric constant of 3.9 across 8–12 GHz, comparable to dielectric materials used in commercial circuit boards. Metallic features reach conductivities up to 3 × 10 7 S/m, approximately half the conductivity of bulk silver, and five orders of magnitude greater than those produced without a photocatalyst under otherwise identical conditions. Using a custom platform that integrates stereolithography and digital light processing, we fabricated wires, multilayer architectures, and functional electronic circuits. This work introduces photocatalysis as a design principle for AM, demonstrating that fabrication can be coupled with spatially programmed chemical synthesis to produce complex and functional multimaterial parts from a single feedstock.