Battery life is a huge issue for smartphone users, and 2012 seems to be the year that manufacturers are taking notice. Last November at the Materials Research Society fall meeting, a team led by Arman Ahnood of the London Centre for Nanotechnology demoed a prototype technology that harvests energy wasted by the display to increase battery life.
According to the team, a typical OLED panel wastes 64 percent of the light produced, a large portion of which escapes the edges of the display. Their prototype uses thin-film photovoltaic cells both within and around the display to capture the wasted light and convert it back into useable energy. Instead of developing complex circuitry to charge the battery of the phone, the team utilized a thin-film supercapacitor for immediate storage. When coupled with the photovoltaic array, the system has yielded an average efficiency of 11 percent, generating just over 1mW per square inch.
As the panel is based on OLED, it's not clear if the technology can be adapted to work with LCD displays, which require a backlight. In any case, it'll take a lot of research and development to turn the prototype into a viable technology that could be used across the industry. Still, even in its state of infancy, there's a lot of potential here.