Black just got blacker

US researchers say they have made the darkest material on Earth, a substance so black it absorbs more than 99.9 per cent of light.

Made from tiny tubes of carbon standing on end, this material is almost 30 times darker than a carbon substance used by the US National Institute of Standards and Technology as the current benchmark of blackness.

And the material is close to the long-sought ideal black, which could absorb all colours of light and reflect none.

"All the light that goes in is basically absorbed," said Pulickel Ajayan, who led the research team at Rice University in Houston.

"It is almost pushing the limit of how much light can be absorbed into one material."

The substance has a total reflective index of 0.045 per cent - which is more than three times darker than the nickel-phosphorous alloy that now holds the record as the world's darkest material.

Basic black paint, by comparison, has a reflective index of 5 per cent to 10 per cent.

The researchers are seeking a world's darkest material designation by Guinness World Records.