Bilayer borophene prevails over monolayer counterpart

Boron (B), the lightest element among the metalloids, shares similar characteristics with carbon in planar and cage molecules. Intensive theoretical studies have predicted a variety of mono-and bi-layer poly -morphs of B with intriguing properties. Single-layer B sheets (borophene) have been experimentally rea-lized on different metal substrates but show poor ambient stability [1,2]. The bilayer (BL) counterpart [3,4], featuring excellent thermal stability and resistance to oxidation, however, remains difficult to prepare. Here, in this Opinion, we highlight recent achievements in the epitaxial growth of BL borophene on noble metal surfaces, and illustrate the crucial roles of the substrate and thermodynamic growth conditions. The su-perior properties of BL over single-layer B sheets are addressed. Experimental realization of BL borophene calls for further exploration of other substrates that may enable phase engineering.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

Boron, the lightest metalloid element, has similar characteristics to carbon in planar and cage molecules. Recent studies have focused on the various structures of mono- and bi-layer boron and their potential applications in materials science. This review highlights the latest achievements in the epitaxial growth of bilayer borophene on noble metal surfaces, discussing the roles of substrate and growth conditions. Bilayer borophene exhibits superior properties compared to single-layer borophene, but its synthesis remains challenging and requires further research.