2D gold ‘nanoseaweed’ could one day be more effective than graphene

6 Aug 2019

Image: © Love the wind/Stock.adobe.com

Researchers have forged the thinnest gold ever recorded in a breakthrough that could revolutionise medtech designs.

Scientists from the University of Leeds have pushed materials science to its limits with gold that would be almost impossible to see. In a paper published to Advanced Science, the researchers announced the creation of a new form of gold just two atoms thick, making it the thinnest unsupported gold ever created.

Its thickness measures just 0.47 nanometres – or 1m times thinner than a human finger nail – and is considered 2D because there are no ‘bulk’ atoms hidden beneath its surface. Tests show this ultra-thin gold is 10 times more efficient as a catalytic substrate than currently used gold nanoparticles classified as 3D for a variety of industrial processes.

However, the researchers said this new material could have massive implications for the medtech and electronics industries, such as forming the basis of artificial enzymes that could be applied in rapid, point-of-care medical diagnostic tests and in water purification systems.

“Not only does it open up the possibility that gold can be used more efficiently in existing technologies, it is providing a route which would allow material scientists to develop other 2D metals,” said Dr Sunjie Ye, lead author of the paper. “This method could innovate nanomaterial manufacturing.”

Two examples of the gold nanosheets with backgrounds coloured turquoise and pink.

The gold nanosheets that are just two atoms thick. Image: University of Leeds

‘We know it will be more effective than existing technologies’

Because of its fragility, shape and the fact it appears green in water, the researchers have dubbed the new nanomaterial as ‘gold nanoseaweed’. Synthesising the material requires an aqueous solution and chloroauric acid, an inorganic substance that contains gold. It is reduced to its metallic form in the presence of a confining agent – the chemical that leads to the gold forming the nanosheet.

What makes the gold nanoseaweed so important, according to research supervisor Prof Stephen Evans, is that its high surface area to volume ratio results in considerable gains.

As the flakes are flexible, he added, they could form the basis of a multitude of electronic components for bendable screens, electronic inks and transparent conducting displays. It will also lead to inevitable comparisons with the first 2D material ever created, graphene, but this new gold might surpass it in usefulness.

“The translation of any new material into working products can take a long time and you can’t force it to do everything you might like to. With graphene, people have thought that it could be good for electronics or for transparent coatings – or as carbon nanotubes that could make an elevator to take us into space because of its super strength,” Evans said.

“I think with 2D gold we have got some very definite ideas about where it could be used, particularly in catalytic reactions and enzymatic reactions. We know it will be more effective than existing technologies – so we have something that we believe people will be interested in developing with us.”

Colm Gorey was a senior journalist with Silicon Republic