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Solar Cells Crystallized Out of Molten Silicon
Hot Toddy sends in a link to a story up on Digital World Tokyo about a more efficient process for manufacturing solar cells. It involves dropping molten silicon from a height of 14 m; surface tension causes tiny spheres 1 mm in diameter to form; the silicon crystallizes in the 1.5 seconds of free-fall. The spheres can be mounted on surfaces of any shape. They capture light from many directions, increasing their solar efficiency. Kyosemi is the company behind the Sphelar technology. Some of the pages on this site date to 2003 and the status of most listed Sphelar products is either "under development" or "engineering sample is available."
For example, the statement about solar panels not having to be flat already applies: there are flexible, stickable (see the UniSolar laminate for example) ones now, with Fresnel lenses etc.
In fact, for many uses, solar is easily laid on an existing flat surface such as a roof. Flat is very often convenient.
The issue about capturing light from any angle is only valid if the individual cells/balls and their connectors (and any surrounding obstacles such as walls and trees) don't get in the way. Multi-layer cells and mechanical trackers and even mirrors mitigate these problems in existing systems: http://www.earth.org.uk/note-on-solar-PV-for-diffuse-light.html
Anyway, interesting, and it would be good to test some in places like the tops of walls, roof ridges, pathways, etc.
Rgds
Damon
http://m.earth.org.uk/
Uh, this looks like the same thing that came out from Spheral Solar Power, that was bought (and later divested) by Automation Tooling Systems:
http://environment.newscientist.com/article/dn3380
Try to hack my 31337 firewall!
That's cool. That is the use of zero G in a manufacturing process, but not for the first time. Shot towers used the same concept to produce spherical lead shot. Zero G manufacturing has been going on for centuries before NASA started getting billions of taxpayers' dollars.
Neat! This is the same method that was used to make cannonballs during the US Civil War.
I can't find any references to cannon ball manufacture on Wikipedia, but my high school had a cannon forming tower (it was originally a civil war arsenal).
Outside of that, the more techniques the merrier! I'm somewhat curious how they create a PN junction out of a homogenous liquid of silicon, but I suppose that can be done afterwards. I'd also be a bit curious if it's single crystalline. I very much doubt it, as there is no seed crystal to nucleate on, so there should be a lot of independent surface nucleation sites (IAAMS).
So nobody's been payint attention to Innovalight in the news lately?
They have the cheaper and more efficient technology:
http://www.news.com/Pour-yourself-a-silicon-solar-panel/2100-11392_3-6213132.html?tag=nefd.top
www1.eere.energy.gov/solar/solar_america/pdfs/41741.pdf
Multiple Exciton Generation is where it's at. Only nanoparticle quantum dots can achieve that, and it's the means to get the highest solar efficiency, because it 's about generating multiple electrons of current for each photon absorbed by your photovoltaic material.
So let me be the first to say it -- ours is bigger than yours!
Do not mock my vision of impractical footwear
Sounds like one of those accidental discoveries...
"Ah crap, I just knocked over the vat of molten silicon we had sitting on the roof ledge!! My boss is gonna be super mad at.... oh hey, look at all these little balls! Weeee, silicon balls!"
http://europe.theoildrum.com/node/3060
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Yeah, but pointing down.
Bert
Is it possible that this will be the new manufacturing that helps push space? It would be interesting to see an automated machine inside of a BA-330, and then have a falcon 9 pick up and drop off.
I prefer the "u" in honour as it seems to be missing these days.
You know, a crystal structure sure has a lot of surface area compared to its weight, maybe, just maybe -- no! definitely, it's an idea, I feel it coming, it's, it's -- a-hem:
I HAVE A DREAM.
I have a dream,
That one day,
Crystallized solar cells will be so light
And so cheap
That you could spray them on a helium balloon.
And that you will.
On half of the balloon.
Only the balloon is parabolic.
And the inside is coated -- half of it,
Yes, forming the shape of a dish,
With something that reflects radiowaves.
And I have a dream
That one day there will be a wireless networking chip so light
And so cheap
That you can buy it in packs of ten.
And you will.
And you will tape it outside that parabolic balloon
Opposite and facing the side
With the insides all radioreflective, facing out like a radar dish.
And the outsides -- the top of the balloon,
And of the part all coated to be radioreflective
Will be crystallized solar cells.
And the power output from the crystallized solar cells
You will run around to power the wireless chip across from the painted side,
Which you will connect with another wireless chip at the base of the balloon,
Facing down.
Into your house.
Repeating the signal.
And then you will fill the balloon with helium and set it free.
Free to float with the wind, tethered to the top of your house.
Four of them, one at each corner of your house.
Turning randomly with the wind.
Like radar dishes.
Only, higher -- much, much, higher.
Like a radio tower.
Because you will tether them with very long string.
And slashdot will report it.
And hundreds of other geeks in your metro area will do the same.
And you will all get good wifi,
Jumping from hotspot to hotspot
As the balloons turn.
And the story will be reposted.
But it will not be a dupe.
Because I have a dream, that the dupe will be with a wireless chip
That does mesh networking.
Yes, one day, in the not so distant future,
Rich little slashdotters and poor little slashdotters
Will fly solar-powered helium balloons
With radio-reflective coated insides,
And mesh networking wireless chips,
And you will forward all the appropriate ports,
And be network neutral,
And it will cost you $7.50
Which will amortize over
Forever.
It's trivial to create a zero-G manufacturing environment here on Earth. The only limitation is that it's only zero-G for a couple of seconds (as it falls down a tower). That is apparently enough for many types of processes such as this one. In space there's no limit on the duration, so growing protein crystals etc might be easier, but the costs of doing anything in space are so enormous that those protein crystals had better be worth thousands of dollars a pound to make them worth doing in space.
Did you see the USB humping dogs? Those really blew me away.
I'm sorry if I haven't offended anyone
Silicon makes everything better... ...especially (ideally) spherical shaped objects...
It is dangerous to be right when the government is wrong.
Disclaimer: Evolution comes with NO WARRANTY, except for the IMPLIED WARRANTY of FITNESS FOR A PARTICULAR PURPOSE.
And Quaker State?
Someone hates these cans.
Missing from the story are important and obvious details.
1. Electrical output efficiency compared to a correctly aimed flat solar panel.
2. How are tiny silicon balls connected to produce electricity?
Any other questions, please chip in.
Thanks, Jim
... hopefully it'll have legs, too.
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
I can't find anything on the site about the actual technique for turning silicon microspheres into cells. How are they prepared, mounted, and connected?
And then they cover the whole thing in rich creamery butter.
The same process with molten glass produces the tiny beads for Scotchlite(TM) reflective material, which has been around for half a century or so.
This is all bullshit, we should be spending trillions on trying to modify the planet's behaviour instead. Now mod me down, thanks.
Someone misled you. Shot (for shotguns) is made in freefall using a tower. And it basically does work the way you're thinking: it doesn't necessarily solidify all the way, but the outside does, and that's enough for it to retain its shape when it hits the water at the bottom of the tower.
Cannonballs were generally made out of cast iron. If you look at an authentic one that's in good shape, you can usually see the mold lines and sprue marks where it was poured. They were usually poured into sand molds that were then knocked away after they cooled.
Some very old cannon balls (prior to the 18th century at least) were cast bronze or cut stone rather than iron, but most people switched to iron as soon as they were able to because it's a harder, cheaper material than bronze, and easier to work with and more effective than stone. (Bronze remained as a material for the cannons themselves well into the 19th century, though, since it has greater tensile strength than cast iron and is less likely to shatter.)
Also, if you think about pouring large quantities of viscous liquid, you'd realize that "dropping" a cannonball wouldn't work; rather than forming a sphere, you'd probably form a teardrop or ellipsoidal shape* due to the air resistance. Forming spheres via freefall cooling is only practical (in normal Earth gravity) for rather small parts, where the surface area to mass ratio is low.
* I'm told that if you look at the shot produced in a shot tower closely enough, all of it is really ellipsoidal rather than truly spherical, but it's such a small difference that it's normally ignored.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
FWIW, they were demonstrating these at the Wired NextFest in Los Angeles last month. I didn't get the details, but they seemed to basically work... at least, they had a curtain of them (several square feet) strung up with several lights pointing at it, and if you blocked the lights with your hands, the toy train that the spheres were powering would stop moving...
I don't care if it's 90,000 hectares. That lake was not my doing.
Multi-layer cells and mechanical trackers and even mirrors mitigate these problems in existing system
Having recently spoken with someone who worked for a solar energy contractor that did large-scale commercial installations, tracking systems double the cost of the system.
Before you scream "zOMG I googled it and they only cost $x dollars", remember that any time you transition from a static system to a dynamic one, complexity and cost go up. It's not just the cost of the tracker device; it's the cost of additional installation work, maybe they need to be calibrated/adjusted individually, maybe they need repair or maintenance, maybe they require a different power hookup method which costs more or takes longer to setup, etc.
Kinda matters when you're installing 500 panels.
Please help metamoderate.
At the moment, we pretty much drill a hole in the ground and start sucking. The energy put in is tiny relative to the energy we get out. As we have to put more energy in to find our energy we have less energy to expend elsewhere. Even nuclear energy has a lower energy return than oil does. When the ratio of energy input to energy output falls to 1:1, the entire economy is employed finding and exploiting new sources of energy. So as we move from oil, the energy sector takes up larger and larger proportions of our spending and investment.
While I don't doubt that market forces will make us move to different fuels, those same market forces may also require us to abandon our cars and skyscrapers. There is nothing magical about the market, it's simply individuals making choices. The reason I asked "is there going to be enough time" is that alternative infrastructures take time, perhaps 10-20 years to build.
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I wonder if you could alter the composition to add colors, or would it interfere with the light collection properties. That way you could string them together in patterns and perhaps apply them on jewelry, that could provide juice for the myriad of electronic gizmo's we cart around every day.
You can find more info and a video with Kyosemi CEO here.
Disclaimer: I work for this company.
The "teardrop" shape only exists while the droplet is suspended from the liquid mass -- it is caused by surface tension trying in vain to attract the droplet to the mass. Once the droplet has separated from the rest of the liquid, then the surface tension is acting evenly in all directions over the surface of the droplet. And that's the only force acting on it (it's in freefall, so no gravity; and we can discount air resistance, because the molten stuff has so much higher a viscosity than the air through which it's travelling).
Now, if the only force acting on the droplet is one that acts evenly in all directions, then what shape do you think it is going to assume?
Je fume. Tu fumes. Nous fûmes!
the nice thing about this (that i forgot until now) is that they aren't just solar cells. working with AIST, a national research center in japan, the cells are also used as sensors to recieve infra-red data from an array of LEDs. this data is converted into electrical signals inside the receiver then sent to a speaker, so they've basically created a wireless, battery-less remote speaker unit. pretty cool... video here and product info here
Nice idea, I'd also check out concentrating solar power though. To me this seems to be a simple, conventional engineering task. Future information here: CSP on The Oil Drum
Actually the sun produces UV light as well, better known as blacklight.
Please, for the good of Humanity, vote Obama.