Printed circuits say hi-ho silver

Researchers at the University of Illinois have emerged from their smoke filled labs having come up with a new way to make cheap printed circuits.

The team has developed an easily-made, more conductive silver ink that can be used in fine-nozzled inkjets.

According to the Journal of the American Chemical Society, which we get for the spot the ionic bond competition, the ink will sort out some of the problems of printing on flexible substrates which are getting more popular with thinner electronic gadgets, wearable devices, and flexible screens.

Hans Thurnauer, professor of materials science and engineering, and Jennifer Bernhard, a professor of electrical and computer engineering, developed the ink which is comprised of silver acetate dissolved in ammonia to give a clear solution.

This is a better system than other inks which are particle based and less predictable. In the reactive ink, the silver remains in solution until the solvent evaporates, leaving a conductive silver deposit.

But the good part is because it is a solution, the ink can be used in inkjet heads or airbrushes with nozzles that are only 100 nanometres in diameter. This is far smaller than is possible with particle inks. It can also be drawn using a pen if you have to.

The other advantage is that the ink remains stable for very long periods. For fine-scale nozzle printing, “that’s a rarity.”

Another use of the ink could be to create mobile phone aerials which could improve reception in lower signal areas, and there are also applications for RFID technology. It will be useful for flexible connectors and also of use for batteries, sensors, and solar energy arrays.