With Photovoltaic Polarizers, electronic devices could be powered by ambient light, sunlight and their own backlight of LCD display screens. We’ve all worried about the charge on our smartphone or laptop running down when we have no access to an electrical outlet. The UCLA engineers have created a novel concept for harvesting and recycling energy for electronic devices — one that involves equipping these devices’ LCD screens with built-in photovoltaic polarizers, allowing them to convert ambient light, sunlight and their own backlight into electricity.

Transparent LCD Display Screen with Polarizing Organic Photovoltaic Film

Transparent LCD Display Screen with Polarizing Organic Photovoltaic Film

LCDs, or liquid crystal displays, are used in many of today’s electronic devices, including smartphones, TV screens, computer monitors, laptops and tablet computers. They work by using two polarized sheets that let only a certain amount of a device’s backlight pass through. Tiny liquid crystal molecules are sandwiched between the two polarizers, and these crystals can be switched by tiny transistors to act as light valves. Manipulating each light valve, or pixel, lets a certain amount of the backlight escape; millions of pixels are combined to create images on LCDs.

The UCLA Engineering team created a new type of energy-harvesting polarizer for LCDs called a polarizing organic photovoltaic, which can potentially boost the function of an LCD by working simultaneously as a polarizer, a photovoltaic device and an ambient light or sunlight photovoltaic panel.

From the point of view of energy use, current LCD polarizers are inefficient, the researchers said. A device’s backlight can consume 80 to 90 percent of the device’s power. But as much as 75 percent of the light generated is lost through the polarizers. A polarizing organic photovoltaic LCD could recover much of that unused energy.