Atmospheric Pressure Plasma Jet Printing for Printed and Flexible Electronics

The emerging field of printed and flexible electronics relies on printing metallic, semiconducting and dielectric layers on various rigid and flexible substrates to fabricate the devices needed in a myriad of applications. Printing of active and passive layers involves lot less logistics and equipment needs compared to conventional micro fabrication. Screen printing, inkjet printing and aerosol jet printing are some of the early techniques serving the needs of printed and flexible electronics. Plasma jet printing is a relatively new approach emerging as an alternative. It is essentially aerosol jet printing aided by or augmented with a plasma in the print head. This low temperature plasma in the form of a dielectric barrier discharge is operated at atmospheric pressure. The energy of the plasma plays a key role in providing a consolidated thin film right away when the plasma stream emerging from the print head nozzle strikes the substrate, thus eliminating altogether or reducing the need for the post-sintering step. When the plasma is off, the ink contents simply get delivered to the substrate as droplets just as in aerosol jet printing, creating the need for further densification and film formation through sintering. This review aims to provide an introduction to plasma jet printing by covering its operating principles, description of printer hardware, printing of metals, semiconductors and others, and applications for plasma-printed films.