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Science

Super-Black Is the New Black (theatlantic.com) 101

Feathers on birds of paradise contain light-trapping nanotechnology that makes some of the deepest blacks in the world, a new study has found. From a report: Blackbirds, it turns out, aren't actually all that black. Their feathers absorb most of the visible light that hits them, but still reflect between 3 and 5 percent of it. For really black plumage, you need to travel to Papua New Guinea and track down the birds of paradise. Although these birds are best known for their gaudy, kaleidoscopic colors, some species also have profoundly black feathers. The feathers ruthlessly swallow light and, with it, all hints of edge or contour. By analyzing museum specimens, Dakota McCoy, from Harvard University, has discovered exactly how the birds achieving such deep blacks. It's all in their feathers' microscopic structure.

A typical bird feather has a central shaft called a rachis. Thin branches, or barbs, sprout from the rachis, and even thinner branches -- barbules -- sprout from the barbs. The whole arrangement is flat, with the rachis, barbs, and barbules all lying on the same plane. The super-black feathers of birds of paradise, meanwhile, look very different. Their barbules, instead of lying flat, curve upward. And instead of being smooth cylinders, they are studded in minuscule spikes. These unique structures excel at capturing light. When light hits a normal feather, it finds a series of horizontal surfaces, and can easily bounce off. But when light hits a super-black feather, it finds a tangled mess of mostly vertical surfaces. Instead of being reflected away, it bounces repeatedly between the barbules and their spikes. With each bounce, a little more of it gets absorbed. Light loses itself within the feathers. McCoy and her colleagues, including Teresa Feo from the National Museum of Natural History, showed that this light-trapping nanotechnology can absorb up to 99.95 percent of incoming light.

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Super-Black Is the New Black

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  • Is this something we could apply solar cells/panels to boost efficiency?
    • by Hal_Porter ( 817932 ) on Tuesday January 09, 2018 @03:16PM (#55895413)

      People have tried.

      https://phys.org/news/2006-06-... [phys.org]

      Silicon surfaces rendered black by pits and bumps only nanometers or billionths of a meter large could in the future help make solar power cells more efficient.

      Flat silicon surfaces are normally highly reflective. Scientists want to minimize reflection as much as possible when it comes to solar power cells made of silicon, because the more light they reflect, the less they convert to electricity. Often, anti-reflective coatings are used, which reduce the amount of average reflection in the wavelengths of light solar power cells use by 85 percent to 92 percent.

      The novel treatment developed by researchers at the Technical University of Munich can cut the surface reflection silicon experiences by 95 percent to 98 percent across the wavelengths of light solar power cells use, making them black.

      "The results are really good when it comes to preventing reflection. It is still speculative as to how much this can boost the efficiency of solar cells. I am optimistic that for traditional designs of solar cells, it could give a 15 to 20 percent improvement with respect to their present efficiency. The performance of some solar cells with novel design could be improved even more dramatically. However, I think we will need a bit of time to show this," said researcher Svetoslav Koynov, a physicist.

      • Heck, even if the efficiency doesn't go up much, it would be great to be able to cut the glare from reflections to minimize issues to air traffic etc. That's always been one of my larger concerns about blanketing large areas with panels.

        • by sudon't ( 580652 )

          ...it would be great...

          Unless Anish Kapoor buys the rights and won’t let anyone else use it.

          • High quality camera lenses have been using nano-coatings for several years. Each manufacturer has its own secret process. It's reasonable to assume that the concept "anti-reflection coating for solar cells" is both too general and too-long established to be properly patented. A specific patent would only cover one nano-coating process, and other processes would be possible.
      • OTOH, any light that is neither reflected nor converted to electricity will heat the panel, and efficiency decreases as panel temperature increases. So ideally it's best to reflect all light that isn't converted.

      • Potassium hydroxide texturing is standard for silicon solar, nothing new. Reflection at the semiconductor level is already 2%, so there is no possible way that better anti-reflection coating alone would improve efficiency by "15-20%" as the physicist in this article seems to think.
    • by lazarus ( 2879 )

      I think it would have more applications to passive solar (heating) panels. The more light you absorb the more heat you capture.

    • That's basically what Solyndra tried (and failed). It's got two basic problems:
      • While the efficiency per square meter of sunlight goes up, the efficiency per square meter of solar panel goes down. So it ends up being more expensive than flat solar panels per unit of energy collected (lower cost efficiency). That extra up-front cost may be worth it on a constrained space such as solar panels aboard a sailboat. But if you've got lots of open land that you can't afford to completely cover with panels in th
  • Blinds and curtains to keep the light out. I bet they would have an incredible insulating factor also.

    • Yeah, but blinds and curtains don't contain "nanotechnology." Bird feathers do, apparently. See, this is why I come to slashdot, I am always learning something new here...
    • Re:Black-Out Blinds (Score:5, Informative)

      by drinkypoo ( 153816 ) <martin.espinoza@gmail.com> on Tuesday January 09, 2018 @04:05PM (#55895793) Homepage Journal

      Blinds and curtains to keep the light out. I bet they would have an incredible insulating factor also.

      The blacker something is, the more energy it radiates in the near infrared. So I'm going to say that they wouldn't improve the insulating factor. In fact, if you exposed the black side, they would reduce it.

      Blackout cloth already blacks out the light sufficiently that the limiting factor is how well you can seal around the edges of your curtains. Exposing the black side would fix this problem, but cause the other problem. The hot outer side of the curtain would heat up the air between the curtain and the glass.

      • Sounds like it would make for a nice set to use in the winter. At least on those days the sun comes through.

      • Re: (Score:2, Insightful)

        by Anonymous Coward

        The hot outer side of the curtain would heat up the air between the curtain and the glass.

        Which, for some of us in Northern climates where is gets Really Fucking Cold might find helpful as it diminishes the heat loss between the air/window into the room.

        Or some kind of skylight which let you have something underneath which gave radiant heat in the house.

        I see lots of applications for being able to translate light into heat. Or at least, places where it would be awfully nice to try. The last few weeks of

        • On those days, you get bright sunshine which leaves no insulation in the clouds, and freezing temps. So any form of light/heat transformation is welcome.

          I remember reading a howto on passive solar heat for one's home by adding a vent near the floor and the ceiling, and adding a glassed-in black strip on the outside of your home. If you don't want heat, you close the vents. You'd probably need the top vent to switch between outside and inside to avoid heat building up there when it wasn't in use, during the summer.

    • by hey! ( 33014 )

      Lining of optical devices to reduce internal reflections.

      I once took a cheap 90mm refractor and took all the steps I could to eliminate internal reflections. It made a huge difference in contrast, for example on images of Jupiter.

    • If you're trying to keep light out then the goal is to reflect it away. The problem with black is it absorbs and thus makes a really horrible insulator.

      Ever notice the inside of your beer cooler is not black?

  • "Technology"? Really?

  • Vantablack (Score:2, Interesting)

    Vantablack has already been invented, move on!
    • Re:Vantablack (Score:5, Insightful)

      by networkBoy ( 774728 ) on Tuesday January 09, 2018 @03:17PM (#55895433) Journal

      actually I wonder if this might count as prior art to open the tech to other manufacturers...

      • actually I wonder if this might count as prior art to open the tech to other manufacturers...

        Nature doesn't count as prior tech, but if this discovery leads to other people being able to make a similar product, then there will be competition and everyone will win.

        The name [Vantablack] comes from [wikipedia.org] the term[s] "Vertically Aligned NanoTube Arrays". If you used nanotubes which were aligned in some other fashion, you probably wouldn't interfere with Vantablack's patents, if any. I'm not aware of any actual patents on Vantablack; WP also says that Vertically aligned nanotube arrays are sold by several fi

        • You know, I'm not actually sure now that I think about it. I'm just so damn cynical I assumed that it had patents on it.

      • The obvious answer is, "It depends."

        If the patent only covers the shape of the surface, then you would have a reasonable argument that the patent would be invalid. I don't think it would technically be considered prior art, instead being evidence that the patent describes something that isn't patentable subject matter (something in nature).

        More likely, though, is that the patent would have to be more specific than just the shape anyway. The patent may describe the exact arrangement of the specific mat
    • Vantablack has already been invented, move on!

      Vantablack absorbs 99.965% of visible light. Which is admittedly better, but to think that these birds have been able to absorb 99.95% of visible light with these feathers for so long is still pretty damn impressive. Especially since it's taken this long do understand why. It's truly impressive how many things we have and can learn from a material science perspective just by looking at what nature has already figured out seemingly at random.

      • Also, you wouldn't want to wear Vantablack clothes due to the danger of breathing in the carbon nanotubes.
        • Also, you wouldn't want to wear Vantablack clothes due to the danger of breathing in the carbon nanotubes.

          And people would try to sit on you in a movie theater.

    • Re:Vantablack (Score:5, Informative)

      by flink ( 18449 ) on Tuesday January 09, 2018 @03:39PM (#55895573)

      Vantablack has already been invented, move on!

      Vantablack has to be grown at 400 C in a furnace, while birds manufacture their feathers somewhere in the neighborhood of 40 C. Far more materials are amiable to being subjected to bird temperatures than Vantablack temperatures. Vantablack surfaces also have to be protected from accidental touching or abrasion, something that bird feathers don't have the luxury of.

      Overall, I think there is probably still quite a bit we can learn from birds. Also, they're just neat.

  • Hopefully in a few years someone can finally build that spaceship for Disaster Area's concert.
  • This gave me an idea: Could you grow silicon crystals in a 3-dimensional pattern that would do what these feathers do? If you could wouldn't you be able to create extremely efficient solar cells?
  • by rsilvergun ( 571051 ) on Tuesday January 09, 2018 @03:15PM (#55895403)
    And the answer is none. None more black.
  • "Feathers contain nanotechnology"... Interesting, who developed that tech and put it on birds? Inquiring minds need to know.
  • “It's like, how much more black could this be? And the answer is none — none more black.”

  • Can someone explain how the light gets 'absorbed'? Does it turn into heat? I'm interested in what happens to the photon as it's getting bounced around in the feather.
  • by Anonymous Coward on Tuesday January 09, 2018 @03:27PM (#55895505)

    Blackbirds, it turns out, aren't actually all that black.

    How dare you? If a bird wants to self identify as being black, who the hell are you to say that they aren't?

    This is just another attempt by the old ivory gull patriarchy to further marginalize an historically oppressed species and deny their cultural identity.

    I can't believe that there wasn't a trigger warning on this post. Don't you know that /. needs to be a safe space, free from the tyranny of archaic ways of thought and ideas and words that are by definition violent?

    • How dare you? If a bird wants to self identify as being black, who the hell are you to say that they aren't?

      Raven Dove-lazal.

  • Super Green

  • ... for Disaster Area's next stunt ship.

  • Blacker than the blackest black, times infinity.

  • by Killer99 ( 469103 ) on Tuesday January 09, 2018 @05:14PM (#55896215) Homepage

    This sounds to me like a VERY good idea for Stealth Tech... of course the size and material would need to be tailored for the wavelengths involved but it's all EM energy....

  • and hank hill is super white!

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