The effect of STW defects on the mechanical properties and fracture toughness of pristine and hydrogenated graphene

Graphene is emerging as a versatile material with a diverse field of applications. Synthesis techniques for graphene introduce several topological defects such as vacancies, dislocations and Stone-Thrower-Wales (STW) defects. Among them STW defects are generated without deleting any atom from the lattice position, but are introduced by rotating single C-C bonds. In this article, molecular dynamics based simulations have been performed to study the effect of STW defects on the fracture toughness of pristine graphene as well as graphene with crack edges passivated with hydrogen atoms. STW defects help in generating out of plane displacement in conjunction with redistribution of stress around the crack edges that can be used to improve the fracture toughness of brittle graphene. An overall improvement in the fracture toughness of pristine graphene as well as graphene containing hydrogen at the crack edges was predicted in this work.