For those who find Google Glass indiscreet, electronic contact lenses that outfit the user's cornea with a display may one day provide an alternative. Researchers at several institutions, including two research arms of Samsung, have already built contacts of this kind, which use new nanomaterials to solve some of the problems that have made contact lens displays less than practical.
A group led by Jang-Ung Park, a chemical engineer at the Ulsan National Institute of Science and Technology, mounted a light-emitting diode on an off-the-shelf soft contact lens, using a material the researchers developed: a transparent, highly conductive and stretchy mix of graphene and silver nanowires. The researchers tested these lenses on rabbits — whose eyes are similar in size to humans — and found no ill effects after five hours. The animals didn't rub their eyes or grow bloodshot, and the electronics kept working. This work is described online in the journal Nano Letters.
To complete this project, they first needed to find a transparent, highly conductive material that was also flexible. The transparent conductor of choice in conventional rigid electronics, indium tin oxide, is brittle, and it must be deposited at high temperatures that can melt a contact lens. Organic conductors, graphene and nanowires are flexible and transparent, but they're not conductive enough.....