Light may be the most abundant resource on Earth and now it can be used to create electricity. The world’s first optical rectenna, part antenna and part rectifier diode, was developed by researchers at Georgia Tech to capture light and turn it directly into DC current. Wildly simplifying the generation of electricity, this crafty little device could really become a game changer in the field of renewable energy.
Other forms of renewable energy – like solar and wind – require a rather involved, multi-step process before usable energy is available. The rectenna converts light directly to DC current, without the need for cooling, and could also be used to create electricity from waste heat. The device is composed of tiny carbon nanotubes and rectifiers that capture light, which doesn’t have to be from the sun. The nanotube antennas create an oscillating charge that moves through the rectifier, switching on and off at record high speeds, thereby creating a small electrical current. Billions of rectennas together can generate a more substantial current.
A breakthrough like this could absolutely revolutionize the clean energy game. “We could ultimately make solar cells that are twice as efficient at a cost that is ten times lower, and that is to me an opportunity to change the world in a very big way,” said Baratunde Cola, an associate professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech.
Rectennas are not a new concept. First developed in the 1960s, the combo technology has been investigated for its potential practical applications. It took over 40 years for researchers to figure out how to make them small enough to couple optical wavelengths, and to make a matching rectifier diode small enough and fast enough to capture the electromagnetic wave oscillations. Because of the enormous potential for efficiency and the low cost of the devices, scientists kept working on the technology. And it’s a good thing they did, because this development could help lead to the most efficient and affordable source of clean energy the world has ever seen.
Images via Georgia Tech