News Article
Researchers close in on the perfect black
Researchers from a number of Universities based at Rice University in Texas have announced the use of carbon nanotubes to create a material that absorbs 99.9 percent of light. The material is almost 30 times darker than a carbon substance that is the current benchmark of blackness.
Pulickel Ajayan, a professor of engineering at Rensselaer Polytechnic Institute, who leads the Rice University team, reported that they created a carpet of carbon nanotubes that reflects 0.045 percent light. Basic black paint, by comparison, has a reflective index of 5 percent to 10 percent.
"All the light that goes in is basically absorbed," said Ajayan. "The final numbers, when we measured how dark this material was, were more dramatic than we expected. It is almost pushing the limit of how much light can be absorbed into one material."
The material could be used in solar energy conversion as the majority of the light will be absorbed. Teamed with technology that could convert light into energy at a high rate we could be looking at the start of truly sustainable energy. The new material could also be used in infrared detection or astronomical observation.
The material is composed of carbon nano-tubes, tiny tubes of tightly rolled carbon that are 400 hundred times smaller than the diameter of a strand of hair. The carbon helps absorb some of the light. These tubes are standing on end, much like a patch of grass. This arrangement traps light in the tiny gaps between blades. The surface of the carbon nano-tube array is irregular and rough to cut down on reflection. It creates a combination of weak reflection matched with high absorption.
So far the material has only been tested on visible light and the next step is to determine is efficiency with infrared, ultraviolet and other wavelengths of light, such as radiation used in communications systems.
"If you could make materials that would block these radiations, it could have serious applications for stealth and defence," Ajayan said.
"All the light that goes in is basically absorbed," said Ajayan. "The final numbers, when we measured how dark this material was, were more dramatic than we expected. It is almost pushing the limit of how much light can be absorbed into one material."
The material could be used in solar energy conversion as the majority of the light will be absorbed. Teamed with technology that could convert light into energy at a high rate we could be looking at the start of truly sustainable energy. The new material could also be used in infrared detection or astronomical observation.
The material is composed of carbon nano-tubes, tiny tubes of tightly rolled carbon that are 400 hundred times smaller than the diameter of a strand of hair. The carbon helps absorb some of the light. These tubes are standing on end, much like a patch of grass. This arrangement traps light in the tiny gaps between blades. The surface of the carbon nano-tube array is irregular and rough to cut down on reflection. It creates a combination of weak reflection matched with high absorption.
So far the material has only been tested on visible light and the next step is to determine is efficiency with infrared, ultraviolet and other wavelengths of light, such as radiation used in communications systems.
"If you could make materials that would block these radiations, it could have serious applications for stealth and defence," Ajayan said.
