Multinozzle 3D printing of multi‐layer and thin flexible electronics

Multilayer flexible electronics have broad applications in the fields of sensors, biomedicine, flexible displays, etc. The existing multilayer flexible electronic manufacturing methods are complicated and usually require multiprocess and multiequipment combinations for processing; especially, it is difficult to achieve integrated manufacturing. The increase in the overall thickness of multilayer flexible electronics also limits its flexibility, stretchability, and spatial density. Herein, a method for integrated multinozzle 3D printing of multilayer flexible electronics with thin structures is proposed and a new strategy for interlayer interconnection is presented. Printing high-viscosity stretchable silver paste on the edge of the multilayer dielectric material and avoiding microholes and vertically printed conductive micropillar structures in traditional interlayer interconnection wires are discussed. The influences of process parameters on the fabrication of multilayer and thin flexible electronics are explored, and the minimum layer thickness for the fabrication of multilayer circuits is determined. A five-layer flexible pressure sensor and two flexible electromagnetic actuators with different coils are fabricated, and the related performance tests of the two devices are carried out. The test results demonstrate that the proposed fabrication method of flexible electronics provides a high-efficiency, low-cost, and simple manufacture solution for the fabrication of multilayer and thin flexible electronics.