Despite the enormous untapped potential of solar energy, one thing is for sure- photovoltaics are only as good as the sun’s rays shining upon them. However, researchers at the Idaho National Laboratory are close to the production of a super-thin solar film that would be cost-effective, imprinted on flexible materials, and would be able to harvest solar energy even after sunset!
The technique involves the embedding of square spirals of conducting metal onto a sheet of plastic, each of which, referred to as a “nanoantenna,” just 1/25 the diameter of a human hair. The nanoantennas absorb infrared energy, which is absorbed by the earth during the day and released even hours after the sun goes down. The nanoantennas are thus able to harvest energy both during daytime hours and into the early evening. Because they can take in energy from both sunlight and the earth’s heat, the nanoantennas have a much higher efficiency (and potential applicability) than conventional solar cells.
The scientific principle isn’t a new one, but the manufacturing process that maximizes efficiency certainly is state-of-the-art. The innovation within nanotechnology is what has allowed the nanoantennas to be efficiently embedded to absorb energy in a flexible and inexpensive material. Just imagine the possibilities…
+ Idaho National Library
+ Solar cells that work at night
So, strictly speaking, these are solar/infrared panels. Not just solar panels.
It’s an interesting concept. We’ll just have to wait and see if they can make it affordable or not.
One thing to not mentioned in the article: For IR panels to work they must be colder than the source of IR. So if the ground is at 70f, the panel must be colder than 70f, preferably much colder, like below freezing. This is hard to do when the air is about the same temperature as the ground. But it does work well for satellites. When they go into earth’s shadow, they get quite cold. Then they could produce power from the IR from Earth.
INL is on a path to absorb ambient IR photons of 8um wavelength at night temperatures with nanoantennae.
But a good antenna is also a good emitter, so net effect is zero if IR panel is also at ambient night temperature.
(It’d emit as many IR photons as it received) Its the thermal difference of sun to earth that’d make this work by day.
But bulk of solar radiation occurs in the visible where photons are less than 1um wavelength. Optimum antennae
shape for both absorption and emission of a photon is a dipole FM antennae where the 2 opposing leads are set
at the halfwave of desired cutoff. For visible light this means lengths of less than 1/2 um somehow interconnected.
There is a viable photon model I’ve used to understand photon interaction with optical surfaces- refraction/scatter.
FYI, go to His magnespheres are representative of the shower of photons we call light.
I love cool stuff like this, I don’t know the in’s and out’s so I can’t comment on the technology itself!
Sounds more like the antennas are absorbing electro magnetic wave energy and when you consider our abundant use of cell phone, microwave and rf use there is no shortage of charged waves floating around even if the cell depends on the harmonics of these transmissions to resonant and attain maximum energy absorbsion.
Bart, no these aren’t IR panels and they do not need to be cooled. Roger, it looks like you’ve got the truth there except for: A good antenna is a good emitter, but only when driven; when acting as a load only partial amount of energy is re-transmitted, not so? But in terms of your day/night argument, I cannot comment and would think that you are right. Additionally I disagree that the optimum shape would be a dipole. What factor are you optimising? Gain? Directivity? Bandwidth?
Just thoughts…
I would like to know what is holding them up? They mention no earth-shattering, insurmountable obstacles?? Not even the down-conversion sounds like a serious problem, though the frequency is a bit up there…
Yeah, I hope they are just at the “how do we fund and mass-produce this” stage already!
-What’s the price??? I’m buying!
-How light is it?
-Does it survive winters/ -30′C?
-How does it work on winter?
If itsurvives -70′C, it can be used on airplanes.
hai, i m from india & this type of invention very helps for our rural people who havent seen electricity yet .pls. send more details on my mail .Thanking you
Ruppal Mandloi Indore M.P.(INdia)
This is going to be good but a few years yet. For now we are still going to need cheap solar panels and they do seem to be dropping in price all the time.
what new in this technology? who knows?
darn..why couldn’t i think of this.
i believe this is surely gonna bring out a revolution in the field of energy as it is we need to throw out the nuclear energy.
I am so very jealous.
i just wanna know when are these IR cells coming to the market.