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Power Science

New Metamaterial Means More Efficient Solar Cells 94

Posted by CmdrTaco from the harness-this-stupid-sun dept.
ElectricSteve writes "Metamaterials are man-made substances designed to do some very weird things that natural materials don't. The path of a beam of light through a natural material like glass is predictable, but scientists from the California Institute of Technology have engineered an optical material that bends light in the wrong direction. This new negative-index metamaterial (NIM) could have several valuable uses including invisibility cloaking, superlensing (imaging nano-scale objects using visible light), and improved light collection in solar cells."
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New Metamaterial Means More Efficient Solar Cells More

New Metamaterial Means More Efficient Solar Cells

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  • Oh noes (Score:5, Funny)

    by Linker3000 ( 626634 ) on Tuesday May 11, 2010 @08:46AM (#32168474) Journal

    ...and frikkin sharks who can fire round corners.

  • I wonder... (Score:3, Funny)

    by Finallyjoined!!! ( 1158431 ) on Tuesday May 11, 2010 @08:47AM (#32168484)
    If we'll finally get real X-Ray Specs now that would be a good use....

    • If we'll finally get real X-Ray Specs now that would be a good use....

      Towards having a germ free adolescents.

    • Given the material is tunable and x-rays are just another wavelength then I don't see why it can't be used. However, as the material merely guides the light rather than lengthening its wavelength, it would cause x-rays to be concentrated onto your retina which may not be the effect you were after.

      Nick

      • However, as the material merely guides the light rather than lengthening its wavelength, it would cause x-rays to be concentrated onto your retina which may not be the effect you were after.

        Or, instead of focusing on it being "x-ray" you focus on getting the same effect with different wavelengths.

        As I recall there were some Sony cameras a couple of years ago then had a "night vision" mode. Turned out that certain fabrics (ie. swimsuits) became effectively transparent when that was enabled during the day.

        Th

        • Re: (Score:1, Funny)

          by Anonymous Coward

          Cheer

          Running so low on cheers that you can only give one out at a time now?

          </kidding>

    • Re: (Score:3, Interesting)

      by codeButcher ( 223668 )

      I'm still holding out for 1-way glass/mirrors that actually WORK AS EXPECTED.

      An ex-gf's father, who is an architect, told me about this super-modern house in the town where he studied that was clad with one-way mirrors. However, after dark, the inside lights would turn them quite see-through. Favourite hang-out for students was by the bedroom wall, no x-ray glasses needed.

      • Re: (Score:3, Informative)

        by khayman80 ( 824400 )

        I'm still holding out for 1-way glass/mirrors that actually WORK AS EXPECTED. An ex-gf's father, who is an architect, told me about this super-modern house in the town where he studied that was clad with one-way mirrors. However, after dark, the inside lights would turn them quite see-through. Favourite hang-out for students was by the bedroom wall, no x-ray glasses needed.

        I said something similar to my undergrad physics advisor while working in experimental optics. He said that "true" one-way glass would p

        • Oops. I meant to say "mirrored box filled with light". Also, next time you're being interrogated in a room with a "one-way mirror", just put your eye right up against the glass and block out ambient light using your hands. You'll probably be able to see into the viewing room unless the viewing room is very dim and/or the interrogation room is very bright.

        • Very interesting - I'm not really well informed in this field.

          It would thus seem that a true one way mirror would not be a passive piece of equipment, but active - taking energy to run.

      • Re: (Score:1)

        by sachamm ( 924766 )

        I'm still holding out for 1-way glass/mirrors that actually WORK AS EXPECTED.

        It's called CCTV... ;-)

    • Re: (Score:2)

      by AGMW ( 594303 )

      If I had an Ass (equus asinus), I'd call it Fanny Front Bottom. Then I could slap my Ass; Fanny Front Bottom, on the Arse.

      There, fixed ya sig for you.

  • Yeah, right. (Score:5, Funny)

    by notgm ( 1069012 ) on Tuesday May 11, 2010 @08:48AM (#32168490)

    I'll believe it when I don't see it.

  • Please explain to me why the title of this news post is "New Metamaterial Means More Efficient Solar Cells" instead of "New Metamaterial Means Kickass Invisibility Cloak"?

    • You must be new here.

      Slashdot Editors do not create the article headline. In fact, "submitters" don't either. Except for a small fraction of submissions, most articles are generated by a specially crafter Slashdot spider, and a random word generator.

      Don't believe me? Go through the front page and see the commonalities.

      Thie headline was generated by the "promise of futuretech" algoritm. Basically: [adjective] [noun (future tech sounding)] [verb] [adjective] [noun (current high tech)]. Other algorithms like "

      • Re: (Score:2)

        by rrhal ( 88665 )
        I'm pretty sure there's a 24th account belonging to a banana slug that lives in one of the danker corners of Cowboy Niel's parent's basement. But it doesn't log in any more - lost interest when the Natalie Portman/Hot Grits meme ran its course.

    • Re: (Score:1, Informative)

      by Anonymous Coward

      Please explain to me why the title of this news post is "New Metamaterial Means More Efficient Solar Cells" instead of "New Metamaterial Means Kickass Invisibility Cloak"?

      Both are equally stupid, but more sexy than "New Metemeterial has Negative Index of Refraction for Visible Light".

    • Please explain to me why the title of this news post is "New Metamaterial Means More Efficient Solar Cells" instead of "New Metamaterial Means Kickass Invisibility Cloak"?

      Well, because the scientists announce it, and what it can do with a bunch of examples. The reporting media reads it, and scratches their head, and picks the only one in the list they understand, and that they think their readers will understand -- everyone knows what a solar panel.

      See, when you're reporting to the lay public, you have to

      • lay public, you have to use words they understand

        Your lay public are dumber than mine if they can't understand these words:

        Kickass
        Invisibility
        Cloak

        Are you sure they passed the initial "Is this people?" test? Pay extra attention to "indicator 32: Does it bark?".

        • Your lay public are dumber than mine if they can't understand these words:

          Kickass
          Invisibility
          Cloak

          *laugh* Well, those three words in combination have a very high geek appeal. But, I can think of a lot of people (who have cleared the "does it bark test") who wouldn't read the article.

          A larger percent of the populace knows what a solar panel is, and would be interested in reading the article. "Kickass Invisibility Cloak" has either bad movie review, or Dungeons & Dragons written all over it. The non-g

          • go to a bar, and try using the words "kickass invisibility cloak" as part of any pickup strategy with a woman of your choice.

            Hmmm... "Hey, do you know where the cloakroom is? ... Hmm, kickass music; it reminds me of Underground Invisibility. Are you into death metal?"

            P.S.: My woman of choice did make me a black cloak, took pictures of me wearing it and then photoshopped it to make it look as an invisibility cloak. True story.

            • P.S.: My woman of choice did make me a black cloak, took pictures of me wearing it and then photoshopped it to make it look as an invisibility cloak. True story.

              Sorry, I guess my implicit qualification of "excluding geek girls" should have been more explicit -- we were, after all, discussing the lay public.

              I'm sure, however, you still get my point. :-P

              Cheers

  • Nothing to see here.

    Somebody got the idea that you could use this stuff to steer light onto solar cells. Reasonable mistake.

    You have to steer a solar cell to follow the sun so it's collecting the most light.

    Steering the light once it's hit the panel is mostly useless-- you're too late -- you're just not intercepting the sun.

    For example if the sun is 45 degrees to the side, you're only getting cos(45) or 70.7% of the rays. Nothing you do at the panel can change that.

    And there are already special reflector

    • You could, in theory, use this to steer light to cells, but is will probably be cheaper just to have bigger arrays.

      The lens is three dimensional. Normally a "thick" lens cannot focus light from multiple angles to the same point. If however the refraction index is modified thoughout the lens so that the lens can focus all of the light comming in to the tall lens from the side goes down to the cell, this is equal to tilting the cell to catch the light.

      The downsides are such a lens will be expensive.

      Even if t

    • Re: (Score:2)

      by Nadaka ( 224565 )

      This is incorrect With meta materials you can get around the issue of directionality of light. With meta materials you can create a spherical receptor several meters in diameter that takes in light from every direction and guides it on to a single solar cell the size of a postage stamp. To do the same thing with a parabolic reflector would still require guidance.

    • While you are probably quite accurate in your post, I think you are missing the point. Though only 70.7% of the light at 45 degrees may be hitting the solar cell, there is additional loss due to reflection and other factors that are inherent to the materials used. So you may only be getting 65% of the actual light at 45 degrees and even less at greater angles (I dont know the math behind this, it was just a hypothetical example). The meta materials do not eliminate the need to steer the panel they only impr

  • I'm just (Score:5, Interesting)

    by Dunbal ( 464142 ) * on Tuesday May 11, 2010 @09:21AM (#32168914)

    Wondering about the time to market in the solar industry, because for the past 2 years I have been reading all about revolutionary new solar cell techniques, from baking your own solar cells in the oven for well under $1/Watt, to solar cells stacked in 3D that increase efficiency to 80%, to dies that help normal solar cells absorb light better, to flexible solar cells that could cover any surface, to special plastics that concentrate light onto solar cells. But you know what? Not a single solar cell on the market today includes these concepts.

    IMO the "cheap, efficient solar cell" will arrive just after the flying car. And the market is certainly resisting current $4-$5/watt retail prices.

    • Re: (Score:2)

      by blueZ3 ( 744446 )

      No, no no.

      The flying car is going to be _powered_ by the cheap, efficient solar cell.

    • Try to be more optimistic - we may get efficient photovoltaic around the time we get commercial fusion power. You know, 20 years in the future (always).
    • Amen. In the meantime, I'll use sun to heat water. Far cheaper and more efficient.
    • So I take it that you only learned to read 2 years ago...
    • Well the flying car is already here [moller.com] and here [terrafugia.com]. So we'll be getting cheap solar soon.

    • Re:I'm just (Score:5, Insightful)

      by bill_kress ( 99356 ) on Tuesday May 11, 2010 @11:59AM (#32171314)

      Solar has a SERIOUS problem that makes it completely resistant to corporate investment... It's that it is virtually impossible to monopolize the market.

      What would you invest in if you were a corporation only interested in your own profits, solar panels that everyone could buy once and put on their roofs for 10 years or a nuclear reactor where you can sell electricity every day of the year at an ever increasing cost? If you picked solar, you've just been fired by the shareholders!

      Although solar is picking up steams, the steps are slower. there is investment in research, research, experimentation, revision, testing, production, mass production--all of which are required to reach "affordable product" (Pulled that out of the air, but I hope you get what I mean)

      Anyway, when you have someone funding that entire cycle at all stages, it moves orders of magnitude faster.

      Actually a corporation might even be better off manipulating the darker/less public parts of a government to hamper solar production--not that anyone would do such a thing.

      • Re: (Score:2, Insightful)

        by Dunbal ( 464142 ) *

        Solar has a SERIOUS problem that makes it completely resistant to corporate investment... It's that it is virtually impossible to monopolize the market.

        I don't understand. Money can be made without monopolies. How many clothing stores are in your shopping mall? How many restaurants sell hamburgers and fries? Or Chinese food. Or fried chicken. Take your pick. The patents on acetaminophen/paracetamol expired a long, long time ago. Yet how many different companies sell this type of pain r

        • Your desktop computer probably tops out at 200W, monitors included. The hot water heater isn't a continuous drain, and neither is the fridge. Sure, it could be better, but you have to look at the overall usage - I use between 15-70KWh/day (electric heat and crappy windows, I think), which works out to about 600-3000W continuous usage. Even with this large amount of consumption, I pay at most $5/day.

          With your solar installation, you can switch to a gas-powered heater and probably only budget for 20 amps or

      • I used to work for an energy conglomerate that was investing heavily in solar. The way it works is that smaller compnies develop and refine until the big ones choose the better ones, buy them and dump money into them. This model has proven successful time and time again. look at the cost of an automobile against average household income over the years. Not only can the average household aford more and better, those cars are required to meet more and stricter requirements. Thr 1940's beetle would get you f

    • IMO the "cheap, efficient solar cell" will arrive just after the flying car. And the market is certainly resisting current $4-$5/watt retail prices.

      What market are you in? Prices have been falling for a while. (Even your quoted numbers are significantly below the $10+ of a few years back, too.)

      If you're willing to accept slight cosmetic defects you can currently get UL-approved panels in quantity for just under $2 or fine working panels without UL approval markings for about $1 (for projects where you don

    • The "cheap, efficient solar cell" arrived about the time pocket calculators came with them.
      We're now looking at extra icing on the cake that allows a wider range of uses.

  • There are an infinite number of ways to generate clean energy. The number of ways which can do so economically, however, is something like (infinity - very few).

    There are an infinite number of ways to cure cancer. The number of ways which can do so without killing the patient, however, is something like (infinity - very few).

    There are an infinite number of ways to store data. The number of ways which can do so usefully, however, is something like (infinity - very few).

    Slashdot needs an "impractical tech ide

    • Re: (Score:2, Insightful)

      by s122604 ( 1018036 )
      And in the late 1800s it was proposed that we would soon have to shut down the patent office, because everything would soon be invented.

      Somehow, I think the issuer of such a proclamation would feel right at home on slashdot

      Yes, virtually all of these ideas, prototypes, theories, etc.. won't pan out. But if one idea in a million pans out, that one idea can still end up changing the world in ways unimagined.

      So yah, keep up the scoffing cynicism, odds are you will be right 99.99% of the time.

      I'd rather

      • >>And in the late 1800s it was proposed that we would soon have to shut down the patent office, because everything would soon be invented.

        sometimes I keep thinking that we have invented everything, then I come to slashdot to find something new and great that has been invented or shoot over to ted ( ted.org ) to gather more insight on what little I know

    • huh? I don't know how to read "(infinity - very few)." Is that (infinity minus very few?) which I think evaluates to "infinity" ...or did you mean something else?

    • Agree with the bulk of your post but ...

      Slashdot needs an "impractical tech idea" category for corralling all the all the grad students working on generating papers about their useless-but-interesting areas of research.

      The problem with such a category is how hard it is to correctly predict WHICH ideas are impractical and which are the next world-changer. The market decides that. If your picks are right significantly more often than a random number generator you could use your leet skillz and invest your l

  • "You've created a new element."

    "Thanks, JARVIS. Now, where the hell is it?"

  • Burying the lede (Score:5, Informative)

    by jfengel ( 409917 ) on Tuesday May 11, 2010 @09:34AM (#32169064) Homepage Journal

    As usual with "SOLAR CELLS HERE TOMORROW!" stories, the actual important news in the story is buried around paragraph six.

    This is not the first time such a material has been developed, but it is the first one that can handle light of any polarity, from any angle. It also works in the blue part of the visible spectrum, making it the first NIM to operate at visible frequencies.

    Ah, thank you. As usual, a nice, modestly useful development of moderate interest to those who study materials engineering, and of essentially zero interest to anybody else. (Well, except for us science nerds, who shouldn't have to be sold the fluff, but it's what we get anyway.)

    But since press releases attract more attention than journal articles, at least when they promise free power, you put FREE SOLAR ENERGY at the top and actual scientific research gets a paragraph somewhere in the middle.

    • To be fair if they put that stuff behind the actual research then nobody would read it. Serious researchers would stop at the end of the research and most other people would give up before even getting to it.

      • Re: (Score:2)

        by jfengel ( 409917 )

        This is true, and I've learned to expect no better from the popular press, which is the target of this press release. (And what we're linked to is a press release, not a journal article.)

        I'd like to think better of Slashdot, but that's not really the case.

        If one actually wants to read science news, I recommend Science News, which does precisely what you suggest: the research in the headline, the speculative applications buried at the end. (And I think they expect their readers always take that with a grai

    • I used to feel somewhat guilty that I'm blocking all ads here while posting whole lotta nonsense. But it turns out, it's a fair deal - I'm getting pretty much what I am paying for.

  • "could have" = we don't know, but give us money (Score:3, Interesting)

    by gweihir ( 88907 ) on Tuesday May 11, 2010 @09:51AM (#32169296)

    I am sick and tired of these "could have tremendous impact bla bla bla" statements. Typically nothing comes out of them in the short term and only tiny improvements to existing solutions in the longer term. Marketing speech sucks and it is time we call it "commercial lies" or maybe with Neil Stephenson "commercial bullshit".

    • Re: (Score:2)

      by marnues ( 906739 )
      Simple fix. Skip them! Times 1 scientific achievement has resulted in instant market application? 0. Get over it and leave it those of us that it does "impact tremendously" alone.

  • Is it theoretically possible to slow down light enough so that it takes a day, month or even a year or two to arrive at the other end of a material? This way you can have a time machine from the past, or use free lighting from the daytime, but at night.

    • Or how about a light flywheel, where light would come in, and enter into a loop, with the photons circling and circling, until you let them out. That way you could collect ambient light for later, and even accumulate it, for flashes.

    • Is it theoretically possible to slow down light enough so that it takes a day, month or even a year or two to arrive at the other end of a material?

      Maybe.

      I recall seeing research indicating that you can and some researchers have. (Down to 38 MPH in 1999, for instance.) But it isn't practical for significant-scale energy storage or expected to become so any time soon.

      No Bob Shaw style "slow glass" this week.

      • Re: (Score:2)

        by Twinbee ( 767046 )

        Interesting. If it could be slowed down to say, 0.0001 mph or less, there could be some really useful apps. Interesting, as it would be a way of storing energy inside an object. What a strange kind of battery that would be.

        • Re: (Score:2)

          by Qzukk ( 229616 )

          really useful apps

          Most likely it'd be used in artistic installations first, eg a hallway that viewed from the outside, shows you the people who walked through a few minutes ago. Perhaps varying the thickness of the material so that people look to be warping around.

          • I did this once, sort of. Video camera into a delay loop to a monitor. Is very interesting watching people watch themselves as they were thirty seconds ago. Quite unlike looking in a mirror.

            • Video camera into a delay loop to a monitor. ... Quite unlike looking in a mirror.

              Doubly so because people's faces are usually slightly asymmetrical and they're used to seeing them reversed in a mirror. So the image looks subtly wrong to them when it's not swapped left-right.

              Portrait photographers know about that and some of them reverse the print if the subject is the customer, so it looks right to him/her and subtly wrong to everybody else. B-)

  • n = c/v. For air, n = 1.000277, so light is slightly slowed down by air. All natural materials slow down light. For diamond, n = 2.417. This helps make diamonds interesting and sparkly. If n 0, then v 0. what does this mean? Is the light traveling backward? or back in time? I am seriously confused. Actually, this does mean that the material has backwards phase propagation. This particular material has n = -2. Ordinarily the group velocity is similar to the phase velocity. But they did not give us enough i

    • Re: (Score:3, Interesting)

      by nickersonm ( 1646933 )

      Not quite. The v in n=c/v is actually the phase speed [wikipedia.org] of the light wave, which is not necessarily the speed at which the pulse of light propagates. The Wikipedia article on negative-index materials has a good animation showing this [wikipedia.org]: the bright bars are the phase peaks, while the envelope is the light pulse. The entire article is pretty good as an overview, although it doesn't go into much mathematical detail.

  • ...to throw the switch (no pun intended) on solar power for my house but every three months I hear of some new material that's supposed to make them cheaper and more efficient.

    Sigh.

    • Re: (Score:1)

      by DanJ_UK ( 980165 ) *
      Even normal people [not geeks] know as soon as you buy a piece of technology it's out-of-date.

  • Here is a link to the actual journal article. [nature.com]

    I would like to point out that the guy promoting the use of negative index materials (NIMs) in solar cells is being extremely optimistic. The Kramers-Kronig dispersion relations require any and all passive NIMs to be inherently lossy at the wavelength of interest. In addition, the wider your try to make the bandwidth, the more loss will incur.

    Don't get me wrong, metamaterials are an extremely interesting field of research, but to promote their use for energy harv

  • It must be at least once a month now that we hear about some advance in solar technology. And yet there are zero of these new cheap and highly efficient options actually in production at the moment.

    Progress in a lab is one thing. We need it in the marketplace for it to really have any impact.

  • Who cares about what possible (unlikely) improvement this would be solar cells. How about camera optics?

    In particular, this NIM would be useful for correcting chromatic aberration [wikipedia.org], which I currently have to correct for planetary imaging in software (which is a bit of a hit-and-miss affair, unfortunately).

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