Light eater

It seems that “invisible” may be the new black. Scientists at Surrey NanoSystems, a British high tech company, have invented a material so black it’s like “looking at a black hole.” They unveiled the material, Vantablack, at a British aerospace and defense trade show last month.

The new material, a result of two years’ development and testing, is not a paint. Rather, it’s a microscopic “forest” of carbon nanotubes on a base of aluminum foil. The name Vantablack is a clue to the technology: Vanta stands for Vertically Aligned Nano Tube Array. Carbon nanotubes are tiny cylinders of pure carbon about one-ten-thousandth the diameter of a human hair. When packed closely together, they allow light photons to come in; but the photons can’t escape. In fact, Vantablack absorbs all but 0.035 percent of the incident light that hits it. By comparison, coal reflects about half a percent or approximately 14 times more light.

Vantablack absorbs so much light that anything coated with it will appear featureless—literally like looking into nothing. At the Farnborough, England, trade show the substance was shown coating a crumpled up piece of aluminum foil. Visitors to the exhibit couldn’t see any of the bends in the foil—it looked completely flat. One British journalist wrote, “If it was used to make one of Chanel’s little black dresses, the wearer’s head and limbs might appear to float incorporeally around a dress-shaped hole.”

While novelty clothing might be interesting, the likely primary application of Vantablack will be to coat the interiors of sensitive telescopes and other optical instruments.

Ben Jensen, Chief Technology Officer of Surrey NanoSystems, says Vantablack “reduces stray-light, improving the ability of sensitive telescopes to see the faintest stars. … Its ultra-low reflectance improves the sensitivity of terrestrial, space and air-borne instrumentation.”

Surrey NanoSystems isn’t discussing it publicly, but the stealth capabilities of a super-black material like Vantablack have created a lot of buzz. Since this material absorbs light across the entire spectrum, from ultraviolet to visible to infrared and microwaves, any weapon system coated with it would be essentially invisible—or at least an unrecognizable black hole. The material’s high vibration resistance and thermal stability make it a good candidate for military and space applications.

Surrey NanoSystems has also patented a low-temperature method for growing the carbon nanotubes, allowing them to be grown on materials compatible with the sensitive electronics of high-flying aircraft and spacecraft. Jensen says his company is scaling up production and has already delivered its first orders.

Apparently, the aerospace industry is not wasting any time getting its hands on the “new black.”

Spray-on solar panels

Scientists at the University of Sheffield have created solar panels using a spray painting process. Employing the common material perovskite instead of traditional silicon makes the sprayed-on panels considerably cheaper to produce—and just as efficient as current solar cells. The spray-on material could turn virtually any surface, including cars and mobile devices, into a solar panel. —M.C.