A new solar tracker maximizes the sunlight solar panels can capture, without using additional electricity to do so.
The system depends on a new material Jiang's team developed, which combines a rubbery material, called liquid crystalline elastomer, with tiny carbon fibers. The fibers are able to absorb a wide range of light, including light waves in the visible and infrared spectrums.
When sunlight falls on the carbon fibers, they heat up. The difference in temperature between the hot carbon fibers and the cooler outside air causes the liquid crystalline elastomer to shrink. When the sun moves on, the material cools and expands again to its original size.
Jiang stood hexagonal solar panels on top of an array of six columns made of his new sun-activated material. Whenever sunlight hit one of the columns, it shrank, tilting the panel on top toward the sun. Compared with solar panels that don't move, the sun-facing panels harvest 10 percent more energy, Jiang's team found.