Defects in Gr/h-BN nanoribbons heterostructure: Atomically precise cutting and defect amplification effect via hydrogenation pseudo-crack

Abstract

Combining both defect and hydrogenation provides the possibility to create an unprecedented structure configuration using an optimally designed mechanical model. The effects of increasing the defect length, coverage of hydrogenation and also the effect of different locations of such defects (Stone-Wales (SW) and vacancy) in hybrid h-BN/Graphene/h-BN nanosheet on their mechanical properties have been studied. The result shows that hydrogenation can be regarded as a kind of pseudo-crack, and even the shape and structure of graphene heterojunction can be precisely controlled and cut. By creating the hydrogenation pseudo-crack in hybrid nanosheets, the carbon atoms in hydrogenated graphene are converted to sp3 hybridization, while the carbon atoms in un‑hydrogenated regions are still sp2 hybridization. The hydrogenation pseudo-crack can also improve the stability and interfacial adhesion of the important region (interface region) of hybrid nanosheets, and transform the sp2 hybridization state into sp3 hybridization state, which can effectively hinder the transformation of six-membered rings in the structure. Only high stress can destroy the structure, so it shows obvious brittle fracture characteristics in the process of tension. Temperature and interface connection also have important influence on the mechanical properties of graphene heterostructure. Defects and hydrogenation pseudo-crack in heterostructures will cause local stress, hybridization state transition and “defect amplification effect”, which will further affect physical properties of materials. In addition, the hydrogenation pseudo-crack is more suitable for atom cutting than vacancy and SW defects, and can precisely control the fracture path of graphene heterostructure.