Thursday, December 17, 2015

Northwetsern and Argonne have synthesized Borophene

Borophene is a proposed crystalline allotrope of boron. Computational studies suggested that extended borophene sheets with partially filled hexagonal holes are stable. Borophene is predicted to be fully metallic and is analogous to graphene in that it is expected to form extended sheets. The latter is a semi-metal, implying that borophene may be a better conductor. The boron-boron bond is also nearly as strong as graphene’s carbon-carbon bond. [Wikipedia]
Borophene sheets. Image: Argonne National Laboratory
Now researchers at Northwestern University and Argonne National Laboratory have found an easy and inexpensive technique  to create borophene. Please check out the full details in the Science paper below.

Synthesis of borophenes: Anisotropic, two-dimensional boron polymorphs

Andrew J. Mannix et al
ScienceVol. 350 no. 6267 pp. 1513-1516, DOI: 10.1126/science.aad1080 

At the atomic-cluster scale, pure boron is markedly similar to carbon, forming simple planar molecules and cage-like fullerenes. Theoretical studies predict that two-dimensional (2D) boron sheets will adopt an atomic configuration similar to that of boron atomic clusters. We synthesized atomically thin, crystalline 2D boron sheets (i.e., borophene) on silver surfaces under ultrahigh-vacuum conditions. Atomic-scale characterization, supported by theoretical calculations, revealed structures reminiscent of fused boron clusters with multiple scales of anisotropic, out-of-plane buckling. Unlike bulk boron allotropes, borophene shows metallic characteristics that are consistent with predictions of a highly anisotropic, 2D metal.