British researchers have shown how graphene can be manipulated to create the most light-absorbent material for its weight.
The researchers from the University of Surrey's Advanced Technology Institute say the nanometre-thin material will enable future applications such as ‘smart wallpaper’ that could generate electricity from waste light or heat, and power a host of applications within the growing ‘internet of things’.
Taking inspiration from nature, they used a technique called nanotexturing, which involves growing graphene around a textured metallic surface.
“Nature has evolved simple yet powerful adaptations, from which we have taken inspiration in order to answer challenges of future technologies,” said Institute head Professor Ravi Silva.
“Moths’ eyes have microscopic patterning that allows them to see in the dimmest conditions. These work by channelling light towards the middle of the eye, with the added benefit of eliminating reflections, which would otherwise alert predators of their location. We have used the same technique to make an amazingly thin, efficient, light-absorbent material by patterning graphene in a similar fashion.”
Silva said graphene has already been noted for its remarkable electrical conductivity and mechanical strength, but for graphene’s potential to be realised as material for future applications, it should also harness light and heat effectively.
Traditionally, graphene is inefficient at light absorption but Silva's team combatted this by using the nano-patterning to localise light into the narrow spaces between the textured surface, enhancing the amount of light absorbed by the material by about 90%.
“Solar cells coated with this material would be able to harvest very dim light. Installed indoors, as part of future ‘smart wallpaper’ or ‘smart windows’, this material could generate electricity from waste light or heat, powering a numerous array of smart applications," he said.
"New types of sensors and energy harvesters connected through the Internet of Things would also benefit from this type of coating.”
He said the next step is to incorporate this material in a variety of existing and emerging technologies.
The graphene is light in weight and light-absorbing. Photo: University of Surrey