Shadows are everywhere. At the moment, we have not yet discovered effective ways to use them in the engineering field, although they are ubiquitous. But now researchers have developed a new device for producing electricity using shadows: this device uses the contrast between light and dark to produce current.
Researchers have developed a new device that exploits the contrast between light points and shadow to create a current, which can power small electronic devices: ” We can harvest energy anywhere on Earth, not only in open spaces, ”says Swee Ching Tan, a materials scientist at the National University of Singapore.
Tan and his research team developed the device called a shadow effect energy generator, by placing a coating of ultra-thin gold on silicon, a typical solar cell material. As in a solar cell, the light that shines on the silicon energizes its electrons. And with the gold layer, the shadow effect energy generator produces an electric current when part of the device is in the shade.
The excited electrons jump from silicon to gold and with a part of the device shaded, the tension of the illuminated metal increases compared to the dark zone, and the electrons in the generator pass from high to low voltage. ” Sending them through an external circuit creates a current that can power a gadget,” reported the research team.
With eight generators, the team managed to operate an electronic watch in low light. Note that these devices can also be used as sensors: when a remote-controlled car passed near the device, its shadow fell on one of the generators, allowing it to create electricity to light an LED.
The greater the contrast between light and dark, the more electricity the generator provides. The team, therefore, seeks to improve the performance of the device by borrowing strategies from solar cells to collect light. The increase in the light absorbed by these generators would indeed allow them to better exploit the shadows.
According to the researchers, “one day, these generators could produce energy in the dark places of a solar panel, between buildings, or even inside”. “ Many people think that shadows are useless. But anything can be useful, even the shadows, ”added Tan.