PV polarizers highlight potential of solar energy
Posted by steve coach on Fri, Nov 25, 2011 @ 02:53 PM
It happens at the worst time. You neglect to charge your smartphone or your laptop computer, and it runs out of juice when you need it the most, and you have no access to an electrical outlet. However, that problem may eventually be a thing of the past, thanks to solar energy and work being done by researchers with the UCLA Henry Samueli School of Engineering and Applied Science.
According to a recent story that appeared on the Science Daily website (www.sciencedaily.com), the UCLA researchers have created a way for electronic devices to harvest and recycle energy. By equipping these devices’ liquid crystal display (LCD) screens with photovoltaic (PV) polarizers, they will be able to convert not only sunlight, but also ambient light and their own backlighting into electricity.
Just about every portable electronic device on the market today has some form of LCD display – it is found on tablet computers, laptops, monitors, smartphones and television screens. These LCDs consist of two polarized sheets of material that let a certain amount of backlight emitted by the device pass through. Between the two polarizers are located miniscule liquid crystal molecules. These crystals can be manipulated by small transistors to act as light valves, which let a certain amount of backlight escape.
But the UCLA team has developed a new kind of polarizer for LCDs, one that harvests energy. It is called a “polarizing organic photovoltaic,” and can work as a polarizer, a PV device and a sun-powered or ambient light PV panel simultaneously. Basically, according to the Science Daily article, the polarizers can act in the same fashion as typical solar cells, turning indoor or outdoor light into energy. For example, an iPhone user could conceivably charge his or her device via sunlight instead of a wall outlet.
According to the article, today’s LCD polarizers are extremely inefficient. A backlight can consume up to 90 percent of a device’s power, but up to 75 percent of that light is lost through the polarizers. A PV LCD, however, could recoup much of that lost energy. The UCLA team is working to increase the efficiency of polarizing organic photovoltaics and hopes to work with device manufacturers to integrate the technology into retail products.
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