[Jedi Master Pikachu]

Aaaaah.

That makes sense. So this probably isn't as helpful for solar energy than a substance which absorbs almost all light would be?

[beezdotcom]

So this probably isn't as helpful for solar energy than a substance which absorbs almost all light would be?

This would work as the A#1 covering for such a substance.

However, the ability to absorb all light is only useful if it then results in a useful transformation of that light energy into something else. Otherwise, black construction paper would make a good solar cell. Kindergartners would rule the world! :-)

[Flightdeck]

The article actually doesn't mention the complex refractive index, which, along with the real index would define the absorptivity/transmittivity (using Fresnel's law). So we just have to assume it is extremely low based on the suggested applications, as beezdotcom pointed out.