UT researchers print electronics via contactless liquid deposition

Researchers from the Mesa+ Institute of the University of Twente have developed a technique with which structures can be printed on the nanoscale, such as electronic circuits, structures for cell research, DNA structures or micro-electromechanical structures.

The technique makes it possible to apply nanoscale liquids to the surface using an electric field without making contact with the print surface. After application, the liquid hardens by evaporation of the solvent. By applying a voltage, the liquid is charged in the tip of the ‘nano fountain pen’. Due to the charge difference with the surface, the liquid is drawn from the tip and deposited on the surface. Depositing or ‘printing’ this can be done very accurately. The liquid must, of course, first be provided with a solvent that must evaporate after the deposition. By using a water-based solvent it is possible to ‘print’ with biomolecules.

The technique developed by the Mesa+ Institute in collaboration with SmartTip is a follow-up to an existing technique in which the ‘dip pen probe’ makes contact with the substrate. Smaller droplets are possible with this technique, up to a minimum of 15 nanometers and in the case of the Twente residents this is at least 70nm, but the dip-pen technique makes the use of a water-based solvent difficult.

The technique presented by the people of Twente makes it possible to apply water-based solutions to hydrophobic or water-repellent surfaces. With a voltage of 60V and a distance of 640nm, the researchers were able to build structures from sodium sulfate. Each ‘droplet’ of around 78nm was obtained by applying a short voltage pulse of 0.5 milliseconds across the pin and the surface.

The researchers hope in the future to make it possible to print various biochemical and electronic components with the technique. The research can be found in the journal Applied Physics Letters.