Inkjet Printed Parallel Plate Capacitors Using PVP Polymer Dielectric Ink on Flexible Polyimide Substrates

Inkjet printing (IJP) is an exciting new additive manufacturing technology that promises monolithic electronic circuit fabrication of $\mu \mathrm{m}$ thin low-cost large-area electronic low-cost body-worn flexible sensors. In this work, we demonstrate inkjet printed multilayer metal-dielectric-metal capacitors on flexible polyimide (PI) substrate by formulating a custom dielectric ink based on Poly 4-vinylphenol (PVP). Silver nanoparticle ink was used for printing theconductive parallel metal plates. We also demonstrate control over the capacitance values by varying the design parameters and succeeded in printing capacitors in the range 8.8 pF to 467 pF, with excellent repeatability on flexible PI substrates. A functional LC circuit using these printed capacitors has been designed and demonstrated to have a resonance frequency of 24.3 MHz. These results are a vital step forward towards monolithic printing of flexible electronic circuits using IJP technique formany applications such as body-worn sensors.