A new material that absorbs 98 to 99 percent of light from all angles has been created by å team of scientists in Saudi Arabia. The King Abdulla University of Science and Technology researchers led by Andrea Fratalocchi developed this blacker than black technology in an effort to promote improved and efficient solar panel technology.
Researchers were inspired by a very white cyphochilus beetle whose shell has scales that form a photonic crystal structure and have an exceptional capacity to reflect light. With its nanomaterial, the team inverted this ultra-white property so they could design a material that would be ultra- black
The study’s findings, published in Nature Nanotechnology, presented a composite nanostructure patterned as a nanoparticle rod attached to a 30nm nanoparticle sphere forming an uneven surface of random gaps with long metallic waveguides. The disordered distribution of pores completely randomizes the reflections of light, providing a source of chaotic light scattering, triggering a process of broadband absorption that creates a completely dark material.
The material is said to disorient perception so that one struggles to comprehend its shape and dimension and is left with a sense of staring into an endless black hole when looking at it.
One interesting possible use of such nanostructures is to harness a wide portion of the solar spectrum and efficiently concentrate it to a single color. This could significantly increase the efficiency of photovoltaic technology. It also opens up the possibility of the use of dark nanomaterials as new types of coherent energy sources.
NASA’s Super-Black Material That Absorbs Light across Multiple Wavelength Bands
In 2011, Nasa engineers developed a super-absorbent material made using a thin coating of carbon nanotubes. These are hollow and multi-walled tubes around 10,000 times thinner than a strand of human hair.
A coating made of this material is seen as black by the human eye and sensitive detectors because the tiny gaps between the tubes collect and trap light, preventing reflection. During tests, it absorbs on average more than 99 percent of the ultraviolet, visible, infrared, and far-infrared light that hits it.
The team has grown the nanotubes on silicon, silicon nitride, titanium and stainless steel, materials commonly used in space-based scientific instruments.
Super-black materials, like the carbon nanotube coating, can be used on devices that remove heat from instruments and radiate it away to deep space. This cools the instruments to lower temperatures, where they are more sensitive to faint signals.
However, these materials rely on organising the carbon nanotubes into thin layers, which means their effectiveness changes based on the angle of the irradiation. By comparison, the latest blackest material, developed by Andrea Fratalocchi and her colleagues at the King Abdullah University of Science and Technology (KAUST) is effective from all angles.
British researchers apply nanotechnology to create super dark material
In 2014, researchers from Surrey NanoSystems took NASA’s breakthrough a step further with its Vantablack material. It absorbs all but 0.035 per cent of light and is so dark the human eye struggles to discern its shape and dimension, giving the appearance of a black hole.
The material is made by densely packed vertically aligned nanotubes grown on sheets of aluminium foil. Vantablack appears completely black because of the radiation absorbant property of carbon nanotubes. It also conducts heat seven and a half times more effectively than copper, and is ten times stronger than steel.
Surrey Nanosystems claims that Vantablack doesn’t have some of the drawbacks of other super-black materials. Vantablack can be produced at lower temperatures than its competition, and it sticks to things better. As a result, Surrey Nanotech could feasibly put more Vantablack in more places. For example, telescopes searching for the oldest sections of the universe can be calibrated using the substance, sensors can be made more sensitive and solar panels can absorb more energy from the sun.
Most of the light is then absorbed as it bounces around creating the illusion of a black hole. It also conducts heat seven and half times more effectively than copper, and is 10 times stronger than steel.
Its ultra-low reflectance shall improve the sensitivity of terrestrial, space and air-borne instrumentation by reducing the amount of noise and thus increase the effective range and resolution. The material is also expected to be used for producing stealthy platforms and weapons.