In this schematic of borophane, the teal balls represent boron and the red balls are hydrogen. Image: Northwestern University.
In this schematic of borophane, the teal balls represent boron and the red balls are hydrogen. Image: Northwestern University.

For the first time, researchers at Northwestern University have created borophane – an atomically thin boron material that is stable at standard temperatures and air pressures. They report this advance in a paper in Science.

Researchers have long been excited by the promise of borophene – a single-atom-thick sheet of boron – because of its strength, flexibility and electronic properties. Stronger, lighter and more flexible than graphene, borophene could potentially revolutionize batteries, electronics, sensors, photovoltaics and quantum computing.

Unfortunately, borophene can only exist inside an ultrahigh vacuum chamber, limiting its practical use outside the lab. By bonding borophene with atomic hydrogen, the Northwestern team has now created borophane, which has the same exciting properties as borophene but is stable outside of a vacuum.

"The problem is that if you take borophene out of the ultrahigh vacuum and into air, it immediately oxidizes," said Mark Hersam, professor of materials science and engineering at Northwestern's McCormick School of Engineering and director of the Materials Research Science and Engineering Center, who led the research. "Once it oxidizes, it is no longer borophene and is no longer conductive. The field will continue to be hindered in exploring its real-world use unless borophene can be rendered stable outside an ultrahigh vacuum chamber."

Although borophene is frequently compared to its super-material predecessor graphene, borophene is much more difficult to create. Graphene is an atomically thin version of graphite, a layered material comprising stacks of two-dimensional sheets. To remove a two-dimensional layer from graphite, scientists simply peel it off.

Boron, on the other hand, is not layered when in bulk form. Five years ago, Hersam and his collaborators created borophene for the first time by growing it directly on a substrate. The resulting material, however, was highly reactive, making it vulnerable to oxidation.

"The boron atoms in borophene are highly susceptible to further chemical reactions," Hersam explained. "We found that once the boron atoms are bonded with hydrogen, they will no longer react with oxygen when in open air."

Now that borophane can be taken out into the real world, researchers will be able to more rapidly explore borophane's properties and its potential applications.

"Materials synthesis is a bit like baking," Hersam said. "Once you know the recipe, it's not hard to replicate. However, if your recipe is just a little off, then the final product can flop terribly. By sharing the optimal recipe for borophane with the world, we anticipate that its use will rapidly proliferate."

This story is adapted from material from Northwestern University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.