Carbon nanotube coating is the new black

MIT engineers developed a coating made from carbon nanotubes that makes for the blackest black, capturing at least 99.995 per cent of incoming light.

In the global race to develop the ‘colourest colour’, black and white are most often the contender as they absorb and reflect the most light respectively. (Read more about the coolest white here).

Leaving the whole Vantablack discussion aside, MIT’s blackest black absorbs 99.995 per cent of any incoming light, which is, according to the researchers, 10 times blacker than anything that’s ever been reported, even blacker than Vantablack.

The ultra-black material was developed by accident, as the researchers were experimenting with ways to grow carbon nanotubes on electrically conducing materials to boost their electrical and thermal properties. On aluminium, however, there is an ever-present layer of oxide that acts as an insulator, blocking rather than conducting electricity. To remove this layer, the aluminium was soaked in salt water. Without the protective layer, the carbon nanotubes could be grown on the aluminium, turning into the blackest black.

With MIT artist-in-residence Diemunt Strebe, the team coated a 16.78-carat natural yellow diamond, estimated at a worth of US $2 million. Normally brilliantly faceted, the diamond has turned into a flat, black void.

While not everyone has the need for an ultra-black diamond, the material could be used practically, for instance for optical blinders that reduce unwanted glade to help space telescopes spot orbiting exoplanets.

Photo: Diemunt Strebe