An all-inkjet printed flexible capacitor for wearable applications

We report on the fabrication of an all-inkjet printed capacitor on a flexible substrate for future use in wearable electronics. Each layer of the capacitor was deposited exclusively using inkjet printing. The capacitor is constructed using the parallel plate structure. A silver nanoparticle dispersion was chosen for the conductive inkjet ink with a curing process of 150 °C for 10 minutes. An inkjet printable photoresist (SU-8) is chosen for the dielectric layer which requires room temperature UV curing for 10 seconds. The theoretical capacitance is calculated to be 48.59 pF using a relative permittivity of 4.2 for SU-8. The discrepancy is around 0.2% to actual capacitance measured at 100 Hz.