Flexible, all metal-oxide capacitors for printed electronics

In this research the use of micron and nanoparticle metal oxide materials for conductive and dielectric screen printing inks were investigated. Screen printed parallel plate capacitors were fabricated to research the applications of these inks. Conductive, micron-particle indium tin oxide (ITO) screen printing inks were formulated for the conductive plates. A dielectric, nanoparticle aluminium oxide (Al2O3) ink was formulated for the dielectric barrier. Capacitors of varying sizes (1cm2 – 9cm2 ) were printed onto flexible polyethylene terephthalate (PET) sheets. The effect of dielectric layer thickness was investigated to find the optimal fabrication process. Impedance analysis was performed on the capacitors to characterise both the performance of the capacitors and the dielectric ink. Analysis of the capacitors was also performed under flex (up to 30% strain) to investigate the effect of bending on the electronic properties. The capacitors were found to be highly stable under bending enabling their use in flexible printed electronics applications.