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The company plans to work with existing solar-cell makers, applying its photonic crystals with a machine added to the solar-cell makers' assembly lines, Bermel says. But StarSolar needs to choose a large-scale manufacturing technique that will allow it to produce the photon crystals inexpensively. What's needed is a way to cheaply arrange two materials in an orderly three-dimensional pattern. For example, microscopic spheres of glass would be arranged in rows and columns inside silicon. Currently, techniques such as e-beam lithography can be used, but that's too slow for large-scale manufacturing.
Shawn-Yu Lin, professor of physics at Rensselaer Polytechnic Institute, has developed a method for manufacturing eight-inch disks of photonic crystal--a measurement considerably larger than what can be done with conventional techniques. The method, which employs optical lithography similar to that used in the semiconductor industry, works best for a type of solar cell that concentrates light onto a small chunk of expensive semiconductor material. Such a device would require a relatively small amount of photonic crystal compared with conventional solar cells. Lin says the technique could be applied for more-conventional solar panels, although it would be expensive.
Another potentially less-expensive method, called interference lithography, creates orderly patterns in the photonic-crystal materials. The method is fast and uses machines that are far less expensive than those used for conventional optical lithography. It also requires fewer steps than Lin's existing process, so he says it could be far cheaper. Such methods have been developed by Henry Smith, professor of electrical engineering at MIT, who was not involved with the StarSolar-related work. Smith says his interference-lithography method could be used to build templates for imprinting photonic-crystal patterns on large areas.
Another promising technique is self-assembly, in which the chemical and physical properties of material building blocks are engineered so that they arrange themselves in orderly patterns on a surface. For example, Chekesha Liddell, professor of materials science and engineering at Cornell University, has engineered building blocks in the shape of peanuts and the caps of mushrooms that line up in rows because of the way they fit together and the tug of short-range forces between them. She says this could be useful for assembling photonic crystals for solar cells.
With such approaches available, Bermel says that StarSolar hopes to have a prototype solar cell within a year and a pilot manufacturing line operating in 2008.
In work that could improve solar cells and LEDs, researchers have, for the first time, made practical working devices out of three-dimensional photonic crystals.
Or, eliminate the back reflector, and . . .
you have a skylight that generates electricity.
Imagine: the solar cell is the top pane of a double paned skylight. The "waste" light is transmitted into your home as illumination, so total efficiency is over 50%.
In fact, every window could generate some PV electricity, especially since if UV, which you want to block anyway, is the most efficient band for PV. There are already PV windows in Germany, I think.
Now if we only had a DC standard so that more appliances ran directly off DC electricity, solar would become even more cost-effective . . .
First, it was the Nano-phosphate Lithium Ion battery (suitable for plug-in hybrid electric vehicles, such as the pending Chevrolet Volt),(which, when available in Austin Texas, can be recharged overnight with our City-owned power companies' surplus overnight Wind energy). (Which, according to Management at Austin Energy, our surplus overnight Wind Energy can recharge 130,000 plug-in 40-mile-on-electric Chevy Volt cars with the breakthrough MIT nano-phosphate Lithium Ion Battery technology at $15 of electricity a month!)
Now, it is a stunning improvement in Solar Cell efficiency (at "grid-Kilowatt cost") (WOW!!) as nearly feasible.
This could significantly change everything for the better as well.
MIT really has changed the flavor of the future in that your advancements have changed the environmental outlook to an extremely bright one.
It's all pretty breath-taking.
If only the rest of the country would keep in touch with MIT.
Sincerely, Dan Petit.
innovations in solar with no real outcomes
I'm frustrated about hearing advances in solar technology with no real production cells that are cheap enough for a middle class family to install and fulfill all their electricity needs. The market is there, what's the hold up??!
why can't we install affordable powerful solar cells today on our homes and cars and start moving towards a renewable energy future away from fosil fuels?
Re: innovations in solar with no real outcomes
Agreed with the comment by amakkar. How many consumers are out there "waiting for the other shoe to drop" regarding solar technology. Personally, every time I read about a technology advancement such as this, I think to myself that I should wait on purchasing any PV system. I don't want make a move similar to buying an 8 track player in 1986 or something.
Re: innovations in solar with no real outcomes
This is a company that is looking to bridge that gap...While there is some criticism, it will be interesting to see how they affect the market.
http://www.citizenre.com/web/index.php
http://en.wikipedia.org/wiki/Citizenre
Maybe I'm a little out of left field with this. What about two way mirror for the outer surface? Opaque side out to collect light and reflective side facing toward the reactive surface? Is it too limited opticly to allow light to pass through?
Another thought came to mind what about optical filters? Certain wavelengths of light are prefered but others just bounce out why not only conentrate on blocking those parts of the spectrum that do not help the proccess?
Guest (supert10)
One way mirrors and filters would block to much of the light coming in. There is a way this could be accomplished and it could be retrofited to exiting solar panels. I am trying to find a way to get my concept to researchers without it being stolen. Not very easy to accomplish in todays ultra competive environment. If my idea works it would allow homeowners to buy the current technology without having to worry about it going totally obsolete in a couple of years. It is obvious that the new solar cells are going to be much more effiecent and that makes investing in the old tech very difficult. I think my concept would benifit the emerging solar cells also. It could get very interesting.
However "exciting" the new solar cell technology
being announced may be... It never seems to reach
the consumer, and when it does, through dealers,
etc. there appears to be so many "middlemen" who's
main motive is to make "big bucks" for themselves.
We need a "Wal-Mart" Solar and Wind power company
made available to consumers, to supply these new
forms of energy at a reasonable cost.
We also need all electric power companies to be
forced to accept (meter reversal) private produced
energy back into their power grids.
Wray
Regarding a 'WalMart for windmills and solar PhotoVoltaics', the market is nearly there...
Currently NorthernToolandEquipment , a general purpose mail order supply house , sells a fair selection of small/home windmills , and some small PV battery-charging setups. I do think that WalMart has plans to sell some of this stuff too. Certainly the online marketplace makes homeowner procurement a feasible option.
Your plea highlights a few present shortcommings, though:
I.) The photovoltaics are even more expensive than the windmills [realizing that winmills only have value in areas with a lot of wind!] , and even those are expensive. The supply needs more mature, and mass-scale production , to increase value.
II.) The demand needs more committment , as willingness to invest in alternatives to the extent people invest in , say , their automobiles.
III.) The society needs to gain more experience with deploying/installing these technologies.
n)... In each case , there is a 'chicken-and-egg' problem , we need move forward.
T m.
electrical current must pass through the photonic crystal. If its made of glass beads or whatever, then the photonic crystal will increase the electrical resistance of the cell.
Also, I think that any lithography step will be cost prohibitive. Solar cells are very price sensitive.
Why not just make the back surface nonplanar, which will tend to reduce the angle of reflected light. This can be done without lithography, by etching the silicon with KOH or other anisotropic etachant. This has already been done. Its not in production anywhere that I know of.
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nekote
139 Comments
Combine with Materials That Reflect No Light
Should be combined with the best anti-reflective surface.
As recently highlighted in TR
Materials That Reflect No Light
http://www.technologyreview.com/Nanotech/18265/
Try to keep as many "captured" photons as possible bottled up - continually reflected, until finally absorbed to produce electricity. Kinda' like some demented early style "Pong" electronic game?
Increasing angle of acceptance and / or some sort of sun tracking would be a further boost.
Reply
bmn
75 Comments
Re: Combine with Materials That Reflect No Light
wasn't there some work done a few years back on mass-producible sheets of micro-concentrators??they were intended to enhance angle of acceptance for solar cells to increase yield. wonder if that is another technology that could be combined here to maximize power out.
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