[SR71]

A Fundamentally Different Solar Technology - This Rocks!

Feb. 27, 2013 — A novel fabrication technique developed by UConn engineering professor Brian Willis could provide the breakthrough technology scientists have been looking for to vastly improve today's solar energy systems.

What kind of breakthrough? Here's the cool part. Instead of relying on the velocity and mass of photons to knock electrons loose like billiard ball collisions from a (typically silicon) substrate to create current flow, this will use use tiny little copper antennas to pull light's EM energy directly from free space to metallic conductors, just the way radio antennas do (well, with an added little very cool twist). This could potentially mean capturing 70% of light's energy, rather than a mere 20% or so in the very best examples of previous technology. That is quite an increase! If it could be manufactured for a comparable cost to silicon based cells, it would absolutely put solar on a favorable cost basis to conventional power!

Here is a super duper cool application of nanotechnology. We haven't been able to do this before, because we simply couldn't make antennas small enough to work at the tiny little wavelengths of much of the sun's spectrum. The antennas can be spaced at a distance that will allow them to capture a continuous band from IR up through visible and UV! Wow! Current technology only captures a small part of that spectrum. Some cells have mixed two bands in the same substrate with some success, but this is way better than that!

Additionally, the antennas have built in little diodes printed in, which allows them to act like rectifiers at the same time they capture the energy! Very nice! I hope this proves practical at industrial scale!

There is still a lot of fiddle fucking around to do, but the guy says it's theoretically possible. Hope they can make it work.

"We've already made a first version of the device," says Willis. "Now we're looking for ways to modify the rectenna so it tunes into frequencies better. I compare it to the days when televisions relied on rabbit ear antennas for reception. Everything was a static blur until you moved the antenna around and saw the ghost of an image. Then you kept moving it around until the image was clearer. That's what we're looking for, that ghost of an image. Once we have that, we can work on making it more robust and repeatable."
Willis says finding that magic point where a rectenna picks up maximum solar energy and rectifies it into electrical power will be the champagne-popping, "ah-ha" moment of the project.
"To capture the visible light frequencies, the rectenna have to get smaller than anything we've ever made before, so we're really pushing the limits of what we can do," says Willis. "And the tunnel junctions have to operate at the speed of visible light, so we're pushing down to these really high speeds to the point where the question becomes 'Can these devices really function at this level?' Theoretically we know it is possible, but we won't know for sure until we make and test this device."