An ink that can deposit silver conductors on cheap substrates such as plastic, paper or fabric has been invented by scientists at the University of Illinois.
Most conductive inks include fine metal particles, whereas the Illinois 'reactive' ink is a transparent solution of silver acetate and ammonia which stays in solution until the liquid evaporates.
"The ink is stable for several weeks, and can print through 100nm nozzles - an order of magnitude smaller than particle-based inks," said the University. "Moreover, its low viscosity makes it suitable for inkjet printing, direct ink writing, or airbrush spraying over large conformal areas."
"For printed electronics applications, you need to be able to store the ink for several months because silver is expensive," explained researcher Brett Walker Walker. "Since silver particles don't actually form until the ink exits the nozzle and the ammonia evaporates, our ink remains stable for very long periods. For fine-scale nozzle printing, that's a rarity."
Lastly, no high-temperature anneal is required.
"The reactive silver ink exhibits an electrical conductivity approaching that of pure silver upon annealing at 90°C," said the University.
