Printed electronics in Italy: from research to business

A. Chiolerio
Istituto Italiano di Tecnologia, IT

Keywords: inkjet, printed electronics

Summary:

Inkjet printing is one of the most promising low cost and environmentally sustainable manufacturing techniques for the deposition of polymeric composites on flexible substrates. Printable inks based on conductive fillers are subjected to several constraints to meet specific conditions, to be ejected through nozzles of micrometric size (20–80 µm). These include the optimization of filler particles size, rheological properties, ink viscosity, surface tension, and solvent evaporation rate. In the latest years, several materials were tested for use as conductive inks, reporting different drawbacks. For instance, conductive polymers and carbon-based materials present the disadvantage of relatively low conductivity, whilst metal nanoparticle-based inks usually need a sintering step, limiting the choice of substrates. Some metals also suffer from oxidation, particularly in the nanoparticle form. This presentation highlights the activities of our Center regarding the synthesis, inkjet printing and characterization of conductive inks, as well as the collaboration with an SME company for testing the innovative formulation developed by us for demanding applications such as microwave power amplification and space qualified devices for sensing / heating. Two routes for the inks fabrication will be reported: (i) an acrylic monomer/GO water-based solution with simultaneous achievement of photo-polymerization and GO reduction; (ii) an intrinsically conductive polymer (polyaniline, PANI) synthesized in a water-based emulsion showing interesting electronic properties such as negative capacitance / supercapacitance. Some other examples of inkjet printed conductive materials will be presented, considering commercial applications.