Structures and nonlinear optical properties of alkali atom/superalkali doped pyridinic vacancy graphene

A new series of alkali atom/superalkali doped pyridinic vacancy graphene, M/pyridinic vacancy graphene and M3O/pyridinic vacancy graphene (M = Li, Na, K), have been theoretically designed and investigated by means of density function theory. It is revealed that all M/pyridinic vacancy graphene compounds can present high NLO with considerable first hyperpolarizability in the range of 7923-8523 au. Moreover, it is found that employing the concept of superalkali unit M3O as the source of the electron can significantly increase the first hyperpolarizability than doping alkali atom. The results show that M3O/pyridinic vacancy graphene exhibit the larger first hyperpolarizability (12199-16553 au), which can be attributed to the lower transition energies. Especially, heavier superalkali can be more powerful in increasing the first hyperpolarizabilities of M3O/pyridinic vacancy graphene. Therefore, M3O/pyridinic vacancy graphene are expected to be potential candidates for NLO materials. We hope that this study could provide a new idea for designing nonlinear optical materials using superalkali clusters.