We sure enjoy the OLED (organic light-emitting diode) screens, since their impressive efficiency means they consume less power than other types of displays, not to mention their potential to make the screens flexible. They work on the principle of electroluminescence — the process of turning electricity into light — and some clever researchers at Cornell University have created OLEDs that can also do the opposite: turn light into electricity. Associate professor George Malliaras led a team to build OLEDs that generate a voltage when exposed to bright light. This seems like the perfect way to build a solar-powered cell phone, notwithstanding the fact that we usually keep phones in our dark pockets and purses when not in use, recharging them during the sunlightless night. But building the new OLEDs into windows would be pretty cool — absorbing energy by day, serving as your TV when the sun goes down. Malliaras's team still needs to improve the efficiency of their creations, but manufacturers aren't exactly tripping over each other to roll out bigger OLED displays anyway. I think he's got time.