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Research Promises Full-Spectrum Solar Cell
nphillips writes "As is being here reported here, a serendipitous discovery was made that a single system of alloys incorporating indium, gallium, and nitrogen can convert virtually the full spectrum of sunlight -- from the near infrared to the far ultraviolet -- to electrical current. For if solar cells can be made with this alloy, they promise to be rugged, relatively inexpensive -- and the most efficient ever created. Solar cells so efficient and so relatively cheap could revolutionize the use of solar power not just in space but on Earth."
Damn, I came up with this idea when I was 12 years old. There go my retirement plans...
As I understand it, UV light hits the earth at all hours.
Does anyone know how much UV hits the earth during the night? If there's more then a trivial amount of light at night, it means that these new solar panels could potentially generate electricity 24 hours a day.
Even if the nighttime energy generation is 1% of the daytime energy generation, it's still a great improvement over today's solar panels.
"Can of worms? The can is open... the worms are everywhere."
Doesn't count, because this article wasn't on the main page.
Heck, anyone with half a testicle could get FP on any of the section pages.
You're a fucking retard...
Better than 70% efficency, versus 25% for current solar cells. Ok, now im willing to accept solar might be feasable.
All Troll + "offtopic" mods are meta moderated as "Unfair", because you abused the system.
How long until Bush and his oil friends squish this research project? I give 12 months...
I just hope that the European and Japanese groups can take up the slack...
Instead of diving into the Iraqi-war-for-oil scheme, we should spend money researching these new solar technologies...
vaporware!
and I quote
"In MBE the components are deposited as pure gases in high vacuum at moderate temperatures under clean conditions."
Further
"If it works, the cost should be on the same order of magnitude as traffic lights," Walukiewicz says. "Maybe less." Solar cells so efficient and so relatively cheap could revolutionize the use of solar power not just in space but on Earth."
-- The morphemes of your disquisition are ascertainable, but they have eschewed an ambit of transpicuous exposition.
What the article didn't mention is that this material could be the killer app for orbital manufacturing. The value of the cells would justify lofting the raw metals into space to form into enormous panels in the open vacuum, free of contaminants. Solar cells with 50% efficiency would compete economically against fossil fuels.
When the article mentioned being able to absorb near infrared light, I was reminded of my ridiculous idea to violate the laws of thermodynamics. Basically, you would need a solar cell that would generate power from infrared light. Use this solar cell to power a battery recharging unit. Place an uncharged battery into the unit, and put it in a dark closet for a year. At room temperature, objects should be giving off black body radiation in the infrared spectrum, so the wall of the closet should be emitting trace amounts of infrared light. So, with enough time, the trickle of current should recharge the battery. Therefore, I have taken heat energy, which is very entropic, and confined it to a battery, thereby decreasing the entropy of the system without expending energy to do it. I know this can't work, but I'm having trouble seeing why. Any ideas?
You're still converting one form of energy into another. That infrared would otherwise be radiating to other objects, increasing their entropy. The infrared produced is tiny compared to the total entropy of the object radiating it, so you could look at it as absorbing the small amount of spontaneous order generated from chaos.
In addition, as I said in the subject, light is light. If one frequency of light can be turned into energy, they all ought to be susceptible to the same concept, if not the same receiver.
Here's a question for you, and for everyone else: Would a solar cell continue to operate in an ambient temperature sufficient to generate that frequency in black-body radiation?
Here's a question for you, and for everyone else: Would a solar cell continue to operate in an ambient temperature sufficient to generate that frequency in black-body radiation?
I *think* the answer is "no", as thermal energy would cause current to flow both ways across the junction you're trying to use to generate power, but as this is not my area of expertise, I could easily be wrong.
Question: How do you make President Bush and his "real" constituency soil their adult diapers? Answer: Have them read the article! To the article authors: Hire some body guards! BTW: You have to wonder how much energy (initially) it would require to manufacture, say, a modest 100 kW solar power plant and the amounts of pollution that manufacturing process would produce. I guess, eventually, with enough solar power plants humming away, providing enough energy to manufacture other solar power plants, this question would be academic.
For utility/residential applications, efficiency isn't very important since there's LOTS of roof area... you can use relatively inefficient technology. What really matters is $/Watt. How much do I have to spend to generate energy equivalent my house's usage?
~gb
I wonder if this material would work well with the previously mentioned Spheral Solar technology people?
http://www.spheralsolar.com/
If the absorbtion range is as good as they said, then one would hope the same method could be used... I guess it is more an issue of the InGaN actually forming spheres.
The article noted that current-best solar cells are about 25% efficient, vs. 30% max. theoretical. How many percent more efficient are you figuring on the new solar cells being if space-made (vs. Earth-made)?
Check out the $billions$ that the dinky space station costs just to keep up. Ditto launch costs for your raw materials & totally unproven zero-grav solar cell factory equipment.
Now spread the extra costs of space-made solar cells out over the number of cells that you think will actually pass QC & reentry. Where do you see the high-volume market willing to pay the $HUGE$ price premium for a few percent better efficiency?
As gbell notes further down, efficiency doesn't mean too much, especially competing against fossil fuels. Cost per watt (call it financial efficiency) is what really matters.
It's easy to make up & spread cool- and credible-sounding stuff. Finding & checking hard facts is hard work.
What about the rest of the EM spectrum. If electricity could be gotten from that, it would be even better.
Traffic lights are not a source of electricity.
someone from the oil and gas industry offers an ungodly sum of money to buy all the tech and research associated with it and then shit cans the whole thing.
Shop smart, Shop S-Mart.
Heinlein described in one of his short stories how some guy using nano-crystals to create the ultimate "cold light source" and noticing that, like most physical processes, this one is works in reverse as well - he's just invented the "perfect" solar collector! Of course the technical specifics are wrong, he got even them pretty close, and he got the basic idea right...
I also loved how he threw in "small" inventions with thought-out consequences into his stories as background. There's a scene I'll always remember where a young cadet-wannabe facing testing answers his father's call on the cell phone while his friend smirks "I tricked my parents - packed the phone in my bags". I bet this scene is replayed with variants all over the world by now. Pretty good for a story written in the 50s or 60s.
Now, where's my budget rental spaceship he was so derogatory about?
Um. Yes. It would. I think. As long as the level of incoming light exceeds the level of the black-body radiation (which is probably very low). I don't think that the black-body radiation is really relevant to the physics of the situation.
However, if you're hot enough for there to be a meaningful amount of black-body radiation in the visible range where many solar cells operate, you're probably hot enough to damage the solar cell anyway.
The big advantage of these cells is that right now a large portion of the suns rays hits our solar panels and efectively bounces off. maybe all the stuff in the infrared and most of the uv. These because they effectivly have a broader frequency response can soak up a larger portion of the energy falling on them.
I don't know if that's the same story or not, but I was remembering one where two scientists invent a full-spectrum solar cell, and the only way they can get it into the world without getting themselves murdered first, is to publish the specs openly and then collect royalties.
:)
Heinlein - he da man!
As an aside, a much more feasible way of vastly reducing our dependency on fossil fuels would be to switch everything feasible over to biodiesel. A lot less pollution, too, as well as better fuel efficiency than gasoline engines, plus the engines are simpler and last longer than gasoline engines (no spark system - diesel engines ignite during the compression process - no spark plugs, etc. needed).
Do a Google search for 'biodiesel' and enlighten yourself.
There was article a little while ago about how they had created a new tungston crystal configuration that would adsorb radiation in a certain spectrum and re-emitt at another. In that case they were adsorbing infrared and re-emitting at visible to wildly increase the efficency of incandencent lights, but IIRC the article said that it could be tuned to a wide range of spectra.
What is keeping them from using this to adsorb the visible spectrum and re-emit at an effecient spectrum from converting to electricity ?
Im not here now... Im out KILLING pepperoni
30% max theo. is with the silicon chips in a narrow spectrum. This is wide spectrum and slightly different material.
What the article doesn't happen to mention is that InAs (Indium Arsenide) was believed to have a bandgap around 1.6eV (not sure the exact number) and it's now known to be somewhere in the range of ~0.6eV. The article also don't mention phosphide compounds, which are far bigger in research and industry right now.
Fact is, nitrides are bastards to grow. You have to use gas-sources (instead of solid sources that most MBE-ers prefer). There's also no current way to make a nitride-based substrate, which means growing (typically) on sapphire or other lattice mis-matched substrates (GaAs, InP, etc). These lead to HUGE dislocation densities that greatly impact performace.
Now, that doesn't mean this can't be done. And in fact, magic is being done all the time in the world of research. But nitrides aren't going to be realized for some time. Not at least until other technologies pan out first (phosphides and the like). Those are cheaper to grow and allow for much lower defect densities.
Just so you folk's know I'm not just talking out of my ars--do some research and look up some papers. Authors to look for are Steve Ringel (OSU), Gene Fitzgerald (MIT), John Carlin (OSU), Sumitomo (Japan, somewhere), and by-far Yamaguchi (Toyota Technological Institute). Read up on these folks' work and those around them--they know space-based photovoltaics better than most, and very, very, very, very few are working with nitrides right now. Not that it's not going to eventually happen--but until defect densities get low enough, there's simply no way to make a good solar cell (read up on the previous authors' works if you want the theoretical calculations as to why).
Long, cute, or funny Sigs are just another form of over compensation, used by geeks, nerdz, etc.
This is an interesting twist on the subject!
The answer is no, as suggested by the Second Law. To see why, you need an account of how solar cells actually work.
Infalling light is absorbed by the material, by dislodging electrons either from a bound orbit, or a semi-free state like a metallic subtrate or semiconductor. The electron absorbs the photon, re-emitting some of the light as another, lower frequency photon, and taking some of the the momentum and energy with it. The new energy and momentum is sufficient to transport it over a potential barrier to the other side of a layered semiconductor or similar. (All semiconductors are layered -- typically they upper few micrometers are doped, wheras lower down it has a different composition).
The solar cell's composition is such that the electron moves up a potential hill, over the brow, and sits in a dip at the top (on the other side of the solar cell). From there, it can get down the hill again (lose it's energy) either by getting over the brow again, or by travelling down the handy attached wires and charging a battery (say).
Imagine if the back of the cell was transparent, and also exposed to sunlight: Then the sunlight falling on that side would knock electrons down the hill as well! This would actually happen EVEN MORE because the work needed to get over the brow out of the little dip at the top is much smaller than the work needed to get all the way up the hill. The difference is that you can't make the electron do any useful work if it is already at the bottom of the hill.
Now if the solar cell is at the same temperature as the black body radiation, the (usually metal or glass) substrate on which the cell is mounted will emit black body radiation too. By the same argument, the equal amount of infalling light from the back of the cell will result in at least as many electrons being knocked down the hill as are being knocked up the hill by the infalling light you want to do the work.
Upshot: The back of the solar cell must be cooler than the temperature of the infalling radiation for it to work.
To clear up a last couple of points: If the back of the cell is not a black-body emitter, it will either be partially transparent or partially reflective or both. There are no other alternatives (because of the quantum symmetries involved). If it is partially transparent, then the temperature of the objects behind the solar cell becomes relevant. If it is partially reflective, the difference is made up by the reflected heat not absorbed by the solar cell -- including the black body radiation of the cell semiconductor if it is not transparent, or the infalling light if it is.
NO ID: BEING FREE MEANS NOT HAVING TO PROVE IT
RTFA. 30% is max efficiency for single-layer cells. Multi-layered cells can get up to 75%.
Now spread the extra costs of space-made solar cells out over the number of cells that you think will actually pass QC & reentry. Where do you see the high-volume market willing to pay the $HUGE$ price premium for a few percent better efficiency?
I thought the original poster was talking about manufacturing panels in space, for use in space.
As gbell notes further down, efficiency doesn't mean too much, especially competing against fossil fuels. Cost per watt (call it financial efficiency) is what really matters.
True, but unless the cost of manufacture scales up faster than the efficiency, this is a win by both criteria.
My deviantArt site
I read the article...you're missing my point. It doesn't matter if the new cells can get 95% efficient - i'm looking at the SPREAD in efficiency between "Made on Earth" and "Made in Space" cells. There is just plain NO WAY that "Made in Space"'s small efficiency boost can justify the MUCH larger cost of manufacture in orbit.
Making panels in space for use in space is interesting...but hard to reconcile with his comment about competing with fossil fuels. Burning fossil fuels for electricity in space has been rather unpopular & uneconomical for quite a few years now.
I don't think this is about (cool idea) large-scale generation of electricity in space to be beamed down to Earth. Nothing i've seen suggests that efficiency of full-spectrum solar cells has anything to do with why that idea isn't flying.
It's easy to make up & spread cool- and credible-sounding stuff. Finding & checking hard facts is hard work.
I smell troll bait...
This is exactly what I thought about when I read this thread. The story is,Let There Be Light, and it featured two scientists (a man and woman) working to create and implement this technology ahead of those from the "power cratels" that wanted to stop them.
This is one of the "earliest" stories in his future history series and forms the basis for much of that history. His story The Roads Must Roll builds on this technology as the power source for his "rolling roads". For a full listing of his short fiction and how it fits together, check out this great site , which appears to be the best Heinlein site on the web.
If efficiency becomes a problem, couldn't we simply put the panels into a low solar orbit, failing that, antimatter is the way of the future, 100% efficency.
You may not agree with what I'm saying but I'll kill you for my right to say it
diesel may have lower CO2 emissions, but they do produce more soot. Result: Lower short-term pollution and global warming, unknown (and potentially much worse) long-term environmental damage.
You may not agree with what I'm saying but I'll kill you for my right to say it
Biodiesel, dude, BIOdiesel - very different from diesel.
Only 30% less emissions than regular diesel, and soot is over 300,000 times better at trapping heat than CO2, which more than makes up for the lower C02 emissions.
You may not agree with what I'm saying but I'll kill you for my right to say it
(a clip from an EPA report):
The Environmental Protection Agency (EPA) has released a new
comprehensive technical report of biodiesel emissions data that shows biodiesel use can reduce
emissions of particulate matter by 47 percent when compared to petroleum diesel in unmodified
diesel engines. The report also verified a 67 percent reduction in unburned hydrocarbons and a
48 percent reduction in carbon monoxide with pure biodiesel (B100).
New scientist says:
Biodiesel made from recycled cooking fat or plant extracts produces 30% less emmisions than regular diesel, but still more than petrol.New scientis also says:
With all things taken into account, 1 gram of black carbon is between 380,000 and 850,000 times as powerful a warming agent than petrol.(admittedly this isn't word-for-word, but it's close)I know who I trust more, it begins with 'N' and ends with 'ew scientist'.
You may not agree with what I'm saying but I'll kill you for my right to say it