Researchers at MIT and Xiamen University in China discovered a number of remarkable properties of borophene, a 2D material that could push graphene out of the limelight.

Graphene is considered to be a wonder material. It consists of a one atom thick sheet of carbon that is incredibly strong, conducts electricity and can form all kinds of shapes. The European Union has invested 1 billion euros to kickstart a graphene industry, and it has been used to make anything from clothing to condoms to paint.

Research into graphene also triggered an interest into other two dimensional materials. One such material is hematene, a material that is 3 atoms thick and extracted from iron ore, which we reported on here.

The latest material to challenge graphene’s claim to the throne is borophene. This material consists of one layer of boron atoms that form various crystalline structures. Borophene has a short history. It was first predicted in the 1990s using computer simulations, but the material wasn’t syntheses until 2015 using chemical vapour deposition. In this process, a hot gas of boron atoms condenses onto a cool surface of pure silver.

The regular arrangement of silver atoms forces boron atoms into a similar pattern, each binding to as many as six other atoms to create a flat hexagonal structure. However, a significant proportion of boron atoms bind only with four or five other atoms, and this creates vacancies in the structure. The pattern of vacancies is what gives borophene crystals their unique properties.

It turns out that borophene is stronger than graphene and more flexible. It is also a good conductor for both electricity and heat, and it superconducts. The properties vary depending on the material’s orientation and the arrangement of vacancies, which means the material is ‘tunable’. In addition, borophene shows promise for use in batteries, and as catalyst in the production of hydrogen.

The main obstacle for ‘the age of borophene’ is that there is no way to produce it in large quantities yet. Additionally, the material is vulnerable to oxidation. Still, borophene has a lot of potential and may just become the new graphene.

Photo: James L. Marshall