The machine that provides power from the shade

A new device harnesses the contrast between points of light and shade to generate an electric current that can power small electronic devices.

“We can capture energy anywhere on Earth, not necessarily in open space,” said Swee Ching Tan, a materials scientist at the National University of Singapore. he created the device, called a shadow-effect generator, by placing an ultra-thin layer of gold on silicon, a key material in solar cells.

Working principle

Just like in a solar cell, light hitting silicon powers its electrons. With that gold layer, the machine generates an electric current when part of the device is in the dark. The excited electrons will jump from silicon to gold. With a part of the device shaded, the voltage of the illuminated metal increases relative to the dark area, and the electrons in the generator current go from high voltage to low voltage. Conducting them through an external circuit generates a current that can power another device.

This machine works on the same principle as a solar battery.

With eight generators, Tan’s team can run an electronic clock in low light. These devices can also act as sensors. When a remote control car passes by, its shadow falls on the generator, creating an electric current to light up the LED. The greater the contrast between light and darkness, the more power the transmitter will deliver. So Tan’s team is trying to increase the efficiency of the device by using the same mechanism that solar cells use to collect light. Increasing the amount of light this machine absorbs will allow them to exploit the darkness more effectively.

These generators could one day generate power in dark spots in a solar array, between skyscrapers or even indoors. “Many people think darkness is useless,” says Tan. But anything can help, even darkness.”

According to Science News.