http://www.digitaljournal.com/tech-and-science/science/the-world-s-thinnest-gold-craeted-by-scientists/article/555669

The world's thinnest gold created by scientists

Posted Aug 10, 2019 by Tim Sandle
Scientists have succeeded in creating a new form of gold, just two atoms thick. This is the e thinnest unsupported gold ever created and it will benefit electronics and medical equipment.
Liquid gold being poured into a cast to make a bullion bar at a Gold Reef City demonstration.
Liquid gold being poured into a cast to make a bullion bar at a Gold Reef City demonstration.
Dan Brown from London, UK (CC BY 2.0)
The new development comes from the Molecular and Nanoscale Physics Group at University of Leeds in the U.K. and the gold that has been fashioned is remarkably thin - just 0.47 nanometres (which is one million times thinner than a human finger nail). The material is also classed as 2D rather than 3D since it comprises just two layers of atoms positioned on top of one another. These atoms are surface atoms, and there are no 'bulk' atoms hidden beneath the surface to created a 3D structure.
The process involves using an aqueous solution based on chloroauric acid plus an inorganic substance containing gold. Through this the gold is reduced to its metallic form via a chemical process that alters the gold to form as a sheet, and this is just two atoms thick.
This is not just a feat of precision chemistry; the new form of gold could have significant benefits for both the medical device and electronics sectors. With electronics, the gold sheets are highly flexible, allowing them to be used in bendable screens, electronic inks and for fashioning transparent conducting displays. In addition, the fold could be used as catalyst to accelerate chemical reactions for industrial processes. With the catalytic process, the researchers are of the view that the gold will be ten times more efficient compared with the gold nanoparticles that serve this purpose today.
With the medical device application, the gold could be used as an artificial enzyme for use in point-of-care medical diagnostic tests. An additional application is with water purification systems, especially for areas without access to a clean supply of water.
According to lead researcher Dr Sunjie Ye: "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." He adds that: "This method could innovate nanomaterial manufacturing."
The research has been published in the journal Advanced Science, in a paper titled "Sub-Nanometer Thick Gold Nanosheets as Highly Efficient Catalysts."