Researchers have combined photovoltaics with LCD screens in a way that could help bolster the battery life of cell phones, UCLA announced Tuesday. By equipping the phones' LCD displays with photovoltaic polarizers, researchers found they could harvest not only the LCD's extra backlight energy, but also ambient light and sunlight.
Normal LCDs have two polarized sheets with liquid crystal molecules between them that let variable amounts of light pass through, depending on what's being displayed on the screen. Light that is blocked or filtered out is effectively wasted energy that can be harvested.
With the new energy harvesters, called polarizing organic photovoltaics, installed in the LCDs, screens could start giving back to the energy stores they greedily deplete all day. A device's backlight consumes 80 to 90 percent of the device's power, the researchers said, and as much as 75 percent of that is lost to the polarizers; if the polarizers were photovoltaic, much of that energy could be recovered. And not only could the LCDs recoup some of their own waste, they could also harvest ambient light and direct sunlight.
The authors don't specify whether the energy-harvesting LCDs use CCFLs or LEDs for backlighting, but since LEDs consume less power in general, results with them would likely be less dramatic. The paper is due for publication in Advanced Materials next month.