Graphene is a bit like the Novak Djokovic of materials – it’s so damn talented that each new achievement feels passé. But now, an exciting new upstart is challenging graphene’s title. Meet goldene, a two-dimensional sheet of gold that has its own strange properties.
It wasn’t long ago that graphene was constantly hogging the headlines, thanks to it being incredibly strong, thin, flexible, lightweight, and an excellent conductor of heat and electricity. And all this from some very humble beginnings – this 'wonder material' was first created by using some sticky tape to peel one-atom-thick layers off a chunk of graphite.
Further experiments were soon giving the stuff even more amazing properties, and it began turning up in electronics, solar panels, displays, clothing, helmets, bullet-proof armor, aircraft, even shoes. But eventually, this overachieving material hit the point of oversaturation in the news and the market – we’re sick of writing about it, you’re sick of reading about it. Even right now, it’s taking up too much space in this story!
Thankfully, there might be a new wonder material ready to steal graphene’s thunder. Researchers at Linköping University in Sweden have successfully created goldene, a sheet of gold that’s only one atom thick. Like graphene, this changes the material’s properties from its 3D bulk form – in this case, goldene becomes a semiconductor, switching from regular gold being one of the best conductors around.
The researchers say that goldene gets its new properties because in its 2D form, the atoms get two “free bonds.” This means it could eventually find use as a catalyst for converting carbon dioxide, producing hydrogen or valuable chemicals, or purifying water. And of course, electronics could benefit, even if it just means less gold is needed to make them.
Goldene didn’t come as easily as graphene, though. Gold atoms have a tendency to clump together, so it’s hard to flatten them out into 2D sheets. The Linköping scientists started by sandwiching thin layers of silicon between layers of titanium and carbide, then coating it in gold. When heated to high temperatures, the thin silicon layer was replaced by gold.
The tricky step then is to get the goldene out of the sandwich. To do so, the researchers tested a chemical called Murakami’s reagent, used as part of an old Japanese blacksmithing technique, which etches away carbon residues. When used in low concentrations for up to two months, the goldene is exposed. Finally, it’s stabilized with a surfactant.
Of course this is just the beginning for goldene, and the researchers say they plan to continue investigating its properties, potential applications, and whether other precious metals could be flattened into two dimensions in similar ways.
The research was published in the journal Nature Synthesis.
Source: Linköping University
