A collaboration of physicists, scientists and businesses have teamed up to create cheap and highly effective solar cells on a nanoscopic scale. Spearheaded by the Idaho National Laboratory, this team is onto a fresh way of producing solar panels that can continue to absorb energy even after the sun has set. The technology, not only efficient at nearly 80%, will also be cheap to manufacture, at estimated pennies a yard.
A specialized manufacturing process will stamp tiny square spirals of a conducting metal onto a think sheet of plastic that have been coined “nanoantennas.” At the slight width on the order of 1/25 the diameter of a human hair, these nanoantennas can absorb energy produced through the infrared spectrum. Infrared energy is produced in massive quantities by the sun, a portion of which is absorbed by the earth only to be released as radiation after the sun has set. These nanoantennas can absorb energy from both the rays of the daylight sun and the heat radiated from the earth at a higher efficiency than modern solar cells.
Steven Novak, a physicist at the Idaho National Laboratory spoke on this technology he is working on at the National Nano Engineering Conference in Boston. He said, “I think these antennas really have the potential to replace traditional solar panels.”
The technology simply mimics that of your cell phone or television antenna, absorbing energy by resonance. The theory that has born the research to produce these nanoantennas was based upon this platform; just make an antenna small enough to absorb the miniscule wavelengths produced by electromagnetic radiation.
The technology behind these atomic sized power modules is nothing new, but it has taken many years to discover an efficient way to print these miniscule spiraled antennas. It wasn’t until the inception of booming advancements in nanotechnology that this fine concept was taken from the theory to the tooling with production of these nanoantennas. The team at the INL forecast seeing the antennas produced akin to that of foil or plastic wrap in rolls of highly efficient solar cells. The team has been able to demonstrate an imprinting process with six-inch circular stamps, with each stamp containing more than 10 million antennas.
Instead of pairing this technology up with conventional solar cells to give them a boost in efficiency, the developers decided instead to make the nanoantennas independent energy harvesters. The team has estimated that individual nanoantennas are capable of absorbing nearly 80 percent of the available energy bombarded onto us daily by the sun. That is a staggering number compared to the conventional panels producing at around 20 percent.
Nanoantennas are not limited to silicon mediums, the circuits can actually be made from a variety of conducting metals and the antennas can be printed onto very thin and flexible materials such as polyethylene. The team has also estimated that the nanoantenna arrays can be available for as much as an inexpensive roll of carpet.
Although the physics of one resonating nanoantenna is certainly achievable, the trick to making this work lies in the matrix of complex vast arrays. The trouble will be in predicting the properties and perfecting the design before tackling the manufacturing obstacles that lie ahead. Multiple antennas create complex and sometimes unpredictable interactions. To jump this hurdle the researchers are developing a computer model of the resonance in these invisible structures, seeking out ways to fine-tune the efficiency of an entire array through tinkering with the materials and shapes of the antennas for example. “The ability to model these antennas is what’s going to make is successful, because we can’t see these things,” says Novack. “They are hard to manipulate, and small tweaks are going to make big differences.”