Recent advances in chemically bonding metal particles allowed the researchers to use silver nanoparticle ink to print the circuits and avoid thermal bonding, or sintering, a time-consuming and potentially damaging technique due to the heat. Printing the circuits on resin-coated paper, PET film and glossy photo paper worked best. Researchers also made a list of materials to avoid, such as canvas cloths and magnet sheets.
Initial reports of the technique, which the team demonstrated at a meeting of the Association for Computing Machinery in Zurich Sept. 10, described the result as a “paper computer,” though the best researchers could do was print a WiFi antenna, circuits for an LED and a 3D-printed flashlight. They also produced circuits containing microprocessors and memory-chip connectors that could potentially become components of an actual device, but the printing, ink and materials are still far too basic to allow that, according to Matt Johnson of conductive-ink manufacturer Bare Conductive, who was quoted in a New Scientist story about the demonstration.