2D Materials: BoropheneLike carbon, boron atoms are capable of…

2D Materials: Borophene

Like carbon, boron atoms are capable of arranging themselves in such a way as to create sheets of the element one atom thick, known as borophene. Unlike graphene, however, the structure of borophene is not exactly flat, and is arranged in clusters of 36 atoms apiece, as shown in the two images above. 

Borophene is mostly theoretical, but some experimental evidence has shown that the structure is indeed possible. Its structure arises from the fact that boron has one fewer electron than carbon, and so cannot form the honeycomb lattice of graphene. This property also leads to a hexagonal vacancy in the center of each B₃₆ cluster. However, borophene of this structure has yet to be created. 

In 2015, borophene was grown for the first time on silver (which does not react chemically with boron) using an ultrahigh vacuum chamber. However, the resulting material was unstable when exposed to air, and not enough has been created yet, or kept stable long enough, to perform experiments testing the new two-dimensional material’s properties. 

Because the work is still mostly theoretical, the most stable phase of borophene, and the best arrangement of its atoms, is still uncertain. The borophene grown on the silver takes the form of a hexagon capped with another boron atom (see source 3), as opposed to the clusters of B₃₆. 

Sources: ( 1 – image 1 ) ( 2 – image 2 ) ( 3 – image 3 ) ( 4 – image 4 ) ( 5 ) ( 6 )

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