New device can produce electricity using shadows? Possible?

One day shadows and light could come together to provide power, a new device harnesses the contrast between bright spots and shadows to create a current that can power small electronic devices. We can harvest energy anywhere on Earth, not just in open spaces, according to materials scientists at the National University of Singapore.

The team of scientists created the device, called a shadow effect power generator, by placing a super-thin layer of gold on silicon, a typical solar cell material, as in a solar plate, the light shining on the silicon energizes its electrons. With the gold coating, the shadow power generator produces an electrical current when part of the device is in the shadow.

Energized electrons jump from silicon to gold, with part of the device shaded, the illuminated metal’s voltage increases relative to the dark area, and the electrons in the generator flow from high to low voltage. Sending them through an external circuit creates a current that can power a device, they report.

Using eight generators, the team ran an electronic clock in low light, the devices can also serve as sensors; as a remote-controlled car passed, its shadow fell on a generator, creating the electricity to power an LED. The greater the contrast between light and dark, the more power the generator provides, so the team is working to increase the device’s performance by borrowing strategies from solar panels to harvest light.

Increasing the light absorbed by these generators would allow them to take better advantage of shadows. One day, these generators could produce power in the dark spots of a solar panel, between skyscrapers, or even indoors.