A new tech developed at UCLA would allow touchscreens to power the phones they were attached to via sunlight or ambient light — even the light thrown off by the screen's own backlight.

Developed at the UCLA Henry Samueli School of Engineering and Applied Science, the prototype LCD screen harvests and recycles energy from any available light. It does so with built-in photovoltaic polarizers, which, while probably not efficient enough to completely power a phone, would certainly make your battery last a lot longer if you kept it in light as opposed to in your pocket all day. We'll see if this ends up making it to any commercial phones in the near future.

Science Daily via TFTS