Substituted graphene nano-flakes: Defective structure and large nonlinear optical property

► Substituted graphenes is a new acceptor-graphene model for NLO materials. ► Three relationships between the defect structure and β0 value are observed. ► We found that the defects can greatly enhance β0 values up to 1.4 × 105 au. ► These show that the defect is a new factor for enhancing β0 value.