Surrey University works on wonder material that absorbs 90 per cent of light
Researchers have created a graphene-based material that generates electricity from waste light or heat. They claim that the substance could power Internet of Things (IoT) devices.
Researchers from the University of Surrey’s Advanced Technology Institute created ultra-thin graphene sheets designed to more effectively capture light. The advance used a technique known as nanotexturing, which involves growing graphene around a textured metallic surface.
Graphene is very strong but traditionally inefficient at light absorption. To get around this problem, used 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 percent.
“Nature has evolved simple yet powerful adaptations, from which we have taken inspiration in order to answer challenges of future technologies,” explained Professor Ravi Silva, head of the advanced technology institute.
“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.”
He said that 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.
“New types of sensors and energy harvesters connected through the Internet of Things (IoT) would also benefit from this type of coating,” he said.
IoT graphene devices
Dr José Anguita of the University of Surrey and lead author of the paper said: “As a result of its thinness, graphene is only able to absorb a small percentage of the light that falls on it. For this reason, it is not suitable for the kinds of optoelectronic technologies our ‘smart’ future will demand.”
“Nanotexturing graphene has the effect of channelling the light into the narrow spaces between nanostructures, thereby enhancing the amount of light absorbed by the material. It is now possible to observe strong light absorption from even nanometre-thin films. Typically, a graphene sheet would have 2-3 per cent light absorption. Using this method, our ultrathin coating of Nano textured few-layer graphene absorbs 95 per cent of incident light across a broad spectrum, from the UV to the infrared.”
Professor Silva said that the next step would be to incorporate this material in a variety of existing and emerging technologies. The team is looking for industry partners to take the research forward.
The research was supported by the BAE Systems for infrared imaging in opto-MEMs devices. The report was published on the 26th Feb edition of the “Science Advances” journal.
Experts welcomed the development. Fred de Haro, CEO of Pycom, told Internet of Business that many environments will require power to connect and it is “essential that this is considered in today’s IoT developments”.
“We, by which I mean technology providers, must consider the implications of such a connected world, be that security or power, and include everything from coffee machines to solar panels and the connected living products yet to be designed,” he said.
Last week, UK-based start-up Zap&Go said it was ready to launch a portable charger for mobile devices that exploits the super capacitive properties of graphene. The charger can be charged up in around five minutes. The technology may replace Lithium ion batteries currently used to power most mobile and IoT devices.