FYI: What's The Darkest Material On Earth?

This material absorbs 99.970 percent of light, making it an ideal coating for solar panels.

By Krislyn Placide Posted 11.14.2012 at 9:00 am 5 Comments

His Darkest Material Courtesy Shawn-Yu Lin

The idea of dark materials might sound familiar to you if you read fantasy trilogies or like casually memorizing lines from Paradise Lost. Unfortunately, this material isn't used to create more worlds--but it might help save this one. Vertically aligned carbon nanotubes (VACNT), the darkest material known to man, was developed by researchers at Rennselaer Polytechnic Institute (RPI) in 2007. With the ability to absorb 99.970 percent of light, VACNT has significant implications in solar energy research. For instance, it can be used to improve the efficiency of solar panels.

Rennselaer's researchers aren't the only ones attempting to produce ultra-dark materials. They've been in a quasi-competition with NASA, which developed a material also made of carbon nanotubes and created using the same process. But at only 99.5 percent absorption, it is not quite as dark as Rennselaer's VACNT.

Into The Nanoforest: Courtesy Shawn-Yu Lin

Why a race for dark materials at all? Isn't regular black paint dark enough to absorb all the colors of light? Conventional black paint and graphite absorb most visible light but reflects a significant amount due to dielectric interface--a moderate reflection of 5 to 10 percent in the air. Researchers found that they could create a super black object by developing long, low-density nanostructures with deep pores, ordered in arrays. In the static electron micrograph, the material looks almost like a forest.

While scientists have not yet reached the goal of achieving near-zero reflection, RPI's dark material--and future, better versions of it--can be used for solar energy conversion and pyroelectric detectors. Since the material absorbs light, it could also be used in cooling applications. No wonder there's a race to perfect it--in a warming world, it could be pretty darn useful.

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5 Comments

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JayArr

11/14/12 at 11:38 am

I wonder how expensive it is to produce 1 square meter of this material? Would it be cost effective, and, more importantly, how would it hold up over time - such that it hopefully pays for itself without needing a lot of maintenance/repair?

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RanoOnay

from Salt Lake City, Utah

11/14/12 at 11:59 am

Looks like a microscopic forest... can be used in collecting and converting solar energy... made out of carbon... sounds like a tiny tree to me! Good thing carbon nano materials are relatively cheap and affordable to produce, go-go green science!

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Robot

11/14/12 at 12:24 pm

Well, until we have a grab bag of dark matter in our hands and can study it under a microscope, it still the most illusive stuff around. And consider the quantity of the stuff that exist, it should be right in our own back yards.

"...In astronomy and cosmology, dark matter is a type of matter hypothesized to account for a large part of the total mass in the universe. Dark matter cannot be seen directly with telescopes; evidently it neither emits nor absorbs light or other electromagnetic radiation at any significant level.[1] Instead, its existence and properties are inferred from its gravitational effects on visible matter, radiation, and the large scale structure of the universe. Dark matter is estimated to constitute 84% of the matter in the universe and 23% of the mass-energy..."
~ http://en.wikipedia.org/wiki/Dark_matter.

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D13

11/14/12 at 1:31 pm

Well collecting this light is one thing, or excuse me "asborbing". In which case the light wave length is basically guided down a dark and small path that breaks the light wave up into more granular photons as it moves deeper into the material.

However, using the absorbed light as energy is quite another thing. Its converting this light to energy that is the crazy part. In fact, if you solve this problem of converting light to energy, then you dont really need the "blackest" material anyways. You would be able to convert the abundance of visible light into enough energy.

That being said, you still need a pretty important second part of this technolgy in order to make a good solar collector/converter of energy.

Now, if the actual nanotubes themselves could make a different charge based on the wavelength of light as it passes through the tubes... mybe reguide the photons back into a loop to collect every last drop, that would be kool.

"Do not try and bend the spoon. That's impossible. Instead... only try to realize the truth. There is no spoon."

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jefro

11/14/12 at 5:43 pm

The ability to absorb light doesn't make it a good choice for solar applications. It would have to be best at the wavelengths that would total most energy. That is not all visible spectrum. Also it would have to be very conductive thermally.