All-printed multilayer high voltage capacitors with integrated processing feedback

Abstract

Template-free 3D printing of electronic devices has the potential to broaden electronics integration to include complex integrated form factors, but success requires precise, adaptive control over materials processing. The development of such manufacturing technologies requires exploration of new combinations of ink sets, printing techniques, and automation strategies. In this work, solution-cast direct-write (SC-DW) was used to print poly(methyl methacrylate) (PMMA) dielectric films with breakdown fields of 790 V/μm, similar to commercially available biaxial-oriented polypropylene (BOPP) films. Furthermore, a complementary composite ink for printing conductive features was developed with conductivities of ˜10,000 Scm-1. A closed-loop feedback system that links deposition parameters with characterization was necessary to maintain μm-precision deposition for over 20 h without human involvement. This closed-loop control scheme enabled 3D printing of both single- and double-layer high-voltage capacitors with capacitances as large as 314 pF (at 1 kHz) and breakdown voltages over 1000 V, which is significant step towards repeatable template-free, 3D printing of electronics for rapid prototyping of multifunctional devices. The precise control over low minimum feature dimension, high breakdown voltage, and long print duration enables the exploration of a broader range of printed electronics application than conventional 3D printing techniques.