Skip to Content

‘Darker Than Black’ Metamaterial Promises Better Solar Cells

Scientists devise a trick to make a material absorb 99 percent of the light that strikes it.
Ordinary black paint absorbs about 85 per cent of the light that hits it. So making something look black simply means ensuring that it absorbs at least as much as this.
Now Evgenii Narimanov at Purdue University and a few colleagues have worked out that they can do much better using a substance called a hyperbolic metamaterial, which absorbs and traps most kinds of light within its structure.
These guys created a hyperbolic metamaterial by growing silver nanowires grown in a membrane of aluminium oxide to create a flat light-absorbing slab. This absorbs some 80 per cent of the light that hit it.
That’s fairly black but then they had an idea. By roughening the surface of the slab, any light that is still reflected gets absorbed in the peaks and troughs of the surface. In effect, the photons are “sucked” into the material, say the team. The result is a substance that absorbs up to 99 per cent of the light that hits it.
Since that’s significantly better than ordinary black paint, Narimanov and co say their substance is darker than black.
There are lots of potential uses for such an idea, not least of which is to improve the efficiency of solar cells.
Ref: arxiv.org/abs/1109.5469 :Darker Than Black: Radiation-Absorbing Metamaterial
Mikhail Noginov and colleagues at Nor In recent years, a number of A standard black paint absorb

Keep Reading

Most Popular

This startup wants to copy you into an embryo for organ harvesting

With plans to create realistic synthetic embryos, grown in jars, Renewal Bio is on a journey to the horizon of science and ethics.

VR is as good as psychedelics at helping people reach transcendence

On key metrics, a VR experience elicited a response indistinguishable from subjects who took medium doses of LSD or magic mushrooms.

This nanoparticle could be the key to a universal covid vaccine

Ending the covid pandemic might well require a vaccine that protects against any new strains. Researchers may have found a strategy that will work.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.