from MIT’s Technology Review:
Researchers at Samsung and Sungkyunkwan University in Korea have come up with a way to capture power when a touch screen flexes under a user’s touch.

The researchers have integrated flexible, transparent electrodes with an energy-scavenging material to make a film that could provide supplementary power for portable electronics. The film can be printed over large areas using roll-to-roll processes, but are at least five years from the market.
