First-principles calculations and classical molecular dynamics simulations were reported which revealed an enhanced defect reactivity induced by an inhomogeneous strain field at grain boundaries. Strained carbon bonds located at heptagons and pentagons could accumulate interstitials and single vacancies, respectively. It was found that recombination of vacancies and interstitials can occur locally at grain boundaries, which serve as effective sinks, resulting in efficient annealing of defects. The enhanced defect reactivity indicates that grain boundaries may be manipulated by point defects.

Strain Enhanced Defect Reactivity at Grain Boundaries in Polycrystalline Graphene. B.Wang, Y.Puzyrev, S.T.Pantelides: Carbon, 2011, 49[12], 3983–8