New research unveils graphene 'moth eyes' to power future smart technologies

February 26, 2016
Solar cells operate by absorbing light first, then converting it into electricity. The most efficient cells needs to do this absorption within a very narrow region of the solar cell material. The narrower this region, the better the cell efficiency. The ability to strongly absorb light by these structures could pave the roadmap to higher cell efficiencies. Credit: University of Surrey

  • New ultra-thin, patterned graphene sheets will be essential in designing future technologies such as 'smart wallpaper' and internet-of-things applications
  • Advanced Technology Institute uses moth-inspired ultrathin graphene sheets to capture light for use in energy production and to power smart sensors
  • Graphene is traditionally an excellent electronic material, but is inefficient for optical applications, absorbs only 2.3% of the light incident on it. A new technique enhances light absorption by 90%.

New research published today in Science Advances has shown how graphene can be manipulated to create the most light-absorbent material for its weight, to date. This 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'.

Using a technique known as nanotexturing, which involves growing graphene around a textured metallic surface, researchers from the University of Surrey's Advanced Technology Institute took inspiration from nature to create ultra-thin designed to more effectively capture light. Just one atom thick, graphene is very strong but traditionally inefficient at . To combat this, the team 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%.

"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."

Graphene has already been noted for its remarkable electrical conductivity and mechanical strength. Professor Ravi's team understood that for graphene's potential to be realised as material for future applications, it should also harness light and heat effectively.

Professor Silva commented: "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 would also benefit from this type of coating."

Dr José Anguita of the University of Surrey and lead author of the paper commented: "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% light absorption. Using this method, our ultrathin coating of nanotextured few-layer graphene absorbs 95% of incident light across a broad spectrum, from the UV to the infrared."

Professor Ravi Silva noted: "The next step is to incorporate this material in a variety of existing and emerging technologies. We are very excited about the potential to exploit this material in existing optical devices for performance enhancement, whilst looking towards new applications. Through Surrey's EPSRC funded Graphene Centre, we are looking for industry partners to exploit this technology and are keen to hear from innovative companies who we can explore the future applications of this technology with us."

The Surrey team developed this technology in cooperation with BAE Systems for infrared imaging in opto-MEMs devices.

Explore further: Scientists show that graphene is highly efficient in converting light to electricity

Related Stories

A new way to make higher quality bilayer graphene

February 8, 2016

(Phys.org)—A team of researchers with members from institutions in the U.S., Korea and China has developed a new way to make bilayer graphene that is higher in quality than that produced through any other known process. ...

Wonder material sparks rush to develop new electronics

February 26, 2016

Bendable mobile phones, quick-charge batteries and unbreakable touch screens—technology firms are racing to harness the potential of graphene, a wonder material which scientists say could transform consumer electronics.

Recommended for you

Graphene under pressure

August 25, 2016

Small balloons made from one-atom-thick material graphene can withstand enormous pressures, much higher than those at the bottom of the deepest ocean, scientists at the University of Manchester report.

Designing ultrasound tools with Lego-like proteins

August 25, 2016

Ultrasound imaging is used around the world to help visualize developing babies and diagnose disease. Sound waves bounce off the tissues, revealing their different densities and shapes. The next step in ultrasound technology ...

Nanovesicles in predictable shapes

August 25, 2016

Beads, disks, bowls and rods: scientists at Radboud University have demonstrated the first methodological approach to control the shapes of nanovesicles. This opens doors for the use of nanovesicles in biomedical applications, ...

Neuromorphic computing mimics important brain feature

August 18, 2016

(Phys.org)—When you hear a sound, only some of the neurons in the auditory cortex of your brain are activated. This is because every auditory neuron is tuned to a certain range of sound, so that each neuron is more sensitive ...

'Artificial atom' created in graphene

August 22, 2016

In a tiny quantum prison, electrons behave quite differently as compared to their counterparts in free space. They can only occupy discrete energy levels, much like the electrons in an atom - for this reason, such electron ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Jeffhans1
not rated yet Feb 26, 2016
I would like to again propose making future solar collectors able to be used as telescopes at night. The power from starlight and reflected sunlight off planets is tiny, but with hundreds of thousands of panels used to create virtual telescope arrays, the resolution would be unimaginable.
nuncestbibendum
not rated yet Feb 29, 2016
We have been hearing about graphene's wonderful properties for - what? A decade? The number of commercially available products making use of such properties is zero. Will this be another DOA?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.