The ink composed of silver nanoparticles is sent through a printing nozzle and then annealed using a laser that applies just the right amount of energy to drive the ink’s solidification. The printing nozzle moves along x, y, and z axes and is combined with a rotary print stage to enable freeform curvature. In this way, tiny hemispherical shapes or spiral motifs made of silver wires less than the width of a hair can be printed in free space within seconds.
The printed wires exhibit excellent electrical conductivity. Localized laser heating enables electrically conductive silver wires to be printed directly on low-cost plastic substrates.