For the first time, researchers have created a free-standing sheet of gold that is only one atom thick. This makes gold the first metal to be formulated into (freestanding) 2D sheets — opening up a host of exciting possibilities for the future.
Creating ‘goldene’, as the one-atom thick material has been named, was not easy for the scientists behind the development, from Sweden’s Linköping University. It is not that such 2D materials have not been created before.
Since the 2004 development of graphene, the atom-thin material made of carbon, scientists have identified hundreds of 2D materials.
However, coming up with atom-thin metallic sheets has been a challenge, due to metals’ tendency to cluster together to make nanoparticles instead. While scientists have previously produced gold sheets sandwiched between other materials, “goldene is the first free-standing 2D metal, to the best of our knowledge,” Lars Hultman, part of the team behind this project, told nature.com.
To create goldene, researchers first sandwiched an atomic monolayer of silicon between layers of titanium carbide. When they deposited gold on top of this sandwich structure, the gold atoms diffused into the material and replaced the silicon atoms, forming a trapped monolayer of gold atoms.
Subsequently, scientists etched away the titanium carbide layers to create a free-standing, one atom thick layer of gold. This was done with the help of an age-old Japanese technique used to forge katanas and high-quality knives, using a chemical popularly known as Murakami’s reagent.
According to Hultman’s estimates, these sheets of gold are roughly 100 nanometers thick (a nanometer is a billionth of a meter), approximately 400 times thinner than the thinnest commercially available gold leaf.
Many potential applications
Developing goldene is not for the purposes of scientific curiosity alone — far from it. Scientists believe that the super thin, super light material can potentially revolutionize the electronics industry.
“Goldene holds promise as a great catalyst because it’s much more economically viable than thicker, three-dimensional gold,” Hultman told sciencenews.org. “You don’t need as many gold atoms to get the same function,” he said. This means that electronics, which use gold due to its electrical conductivity, can potentially use lesser amounts for the same purpose.
Furthermore, the technique used by scientists to create golden can, in theory, also be applicable to other metallic objects. Shun Kashiwaya, co-author of the study and a materials scientist at Linköping University, said that the team is already working to make 2D sheets of iridium and platinum.
Lastly, goldene possibly also has some special properties, like other previously developed 2D materials. This is due to the fact that each gold atom, in this case, has only six neighboring atoms, compared to 12 in a three-dimensional crystal. Scientists say that future applications could include carbon dioxide conversion, hydrogen-generating catalysis, selective production of value-added chemicals, hydrogen production, water purification, etc.
