High resolution electrohydrodynamic jet printing for flexible electronics

Efforts to adapt and extend graphic arts printing techniques for demanding device applications in electronics, biotechnology and microelectromechancial systems have grown rapidly in recent years. This paper describes the use of electrohydrodynamically induced fluid flows through fine microcapillary nozzles for jet printing of patterns and functional devices with sub-micron resolution. Key aspects of the physics of this approach, which has some features in common with related but comparatively low resolution techniques for graphic arts, are revealed through heuristic models and direct high speed imaging of the droplet formation processes. Printing of complex patterns of inks, ranging from insulating and conducting polymers, to solution suspensions of silicon nanoparticles and rods, to single walled carbon nanotubes, using integrated, computer controlled printer systems illustrates some of the capabilities. High resolution, printed metal interconnects, electrodes and probing pads for functional transistors and representative circuits with critical dimensions as small as 1 micron demonstrate potential applications in printed electronics.