Gold is a key element for electronic devices, and since those devices are always shrinking, engineers need to find ways to make smaller components too. On that path, scientists from the University of Leeds have managed to make the thinnest gold ever created, measuring just two atoms thick. That makes it functionally two-dimensional, joining the likes of graphene.
The record-breaking gold was measured to be just 0.47 nanometers thick, which is roughly a million times thinner than a human finger nail. Made of just two layers of gold atoms on top of one another, this is the thinnest gold ever created that wasn't supported by a substrate.
Because all the individual gold atoms are on either of the two surfaces and there aren't any in the middle, the team regards these sheets of gold as a 2D material. That's slightly different to things like graphene, which is made up of sheets just a single atom thick.
The ultra-thin gold sheets are made from chloroauric acid, which is an inorganic substance that contains gold. When a confinement agent is added, the gold is reduced to its metallic form, with its atoms stacking into a 2D lattice.
The team says this form of gold could be used in several of the applications that gold nanoparticles are currently used for. In electronics, these thin sheets not only reduce the amount of gold needed – which saves on cost for the precious metal – but they can be flexible, allowing for electronic inks and maybe bendable displays.
Gold is also a common catalyst for chemical reactions in industry, and the team found that these atomically-thin gold sheets were up to 10 times more efficient at this process than the nanoparticles normally used.
"Gold is a highly effective catalyst," says Stephen Evans, supervisor of the research. "Because the nanosheets are so thin, just about every gold atom plays a part in the catalysis. It means the process is highly efficient. Our data suggests that industry could get the same effect from using a smaller amount of gold, and this has economic advantages when you are talking about a precious metal."
This new form of gold could also be used as the basis of artificial enzymes, which could be used in medical diagnostic tests or water purification systems.
The research is published in the journal Advanced Science.
Source: University of Leeds
