Anomalous Strength Characteristics of Tilt Grain Boundaries in Graphene

Abstract

Perfect Imperfections: Graphene is composed of six-atom rings, but will include a number of five- and seven-atom rings as defects. Using simulations, Grantab et al. (p. 946 ) show that more defects do not necessarily lead to greater deterioration of mechanical properties. Mismatches caused by differences in the orientation of neighboring crystals are divided into low- and high-angle grain boundaries, and typically it is the lower-angle boundaries that are stronger. In graphene, by contrast, the larger-angle boundaries, which consist of higher-defect densities, are better able to accommodate the strain and prevent failure that originates in the breakup of the seven-member graphene rings. This suggests ways for synthesizing imperfect graphene sheets that will have mechanical properties that are close to those of perfect graphene.