Mechanical properties of atomically thin boron nitride and the role of interlayer interactions

TLDR

Atomically thin boron nitride nanosheets are important two‑dimensional nanomaterials with many unique properties distinct from those of graphene, but investigation into their mechanical properties remains incomplete. The difference in mechanical behavior between BN and graphene under indentation is attributed to distinct interlayer interactions and sliding tendencies. High‑quality single‑crystalline mono‑ and few‑layer BN nanosheets are among the strongest electrically insulating materials, and unlike graphene, their mechanical strength is insensitive to thickness, making BN a more attractive candidate for mechanical reinforcement applications.

Abstract

Abstract Atomically thin boron nitride (BN) nanosheets are important two-dimensional nanomaterials with many unique properties distinct from those of graphene, but investigation into their mechanical properties remains incomplete. Here we report that high-quality single-crystalline mono- and few-layer BN nanosheets are one of the strongest electrically insulating materials. More intriguingly, few-layer BN shows mechanical behaviours quite different from those of few-layer graphene under indentation. In striking contrast to graphene, whose strength decreases by more than 30% when the number of layers increases from 1 to 8, the mechanical strength of BN nanosheets is not sensitive to increasing thickness. We attribute this difference to the distinct interlayer interactions and hence sliding tendencies in these two materials under indentation. The significantly better interlayer integrity of BN nanosheets makes them a more attractive candidate than graphene for several applications, for example, as mechanical reinforcements.