▎ 摘　　要

The graphenes and polyoxometalates (POMs) have been investigated individually for finding a material with intrinsic nonlinear optical (NLO) behaviours. In this study, we designed a novel molecular hybrid containing POM cluster linked with nanographene. We could be able to design a material with very large second-order NLO response. The Coulomb-attenuating method (CAM-B3LYP) is used with the LANL2DZ basis set for molybdenum atoms and both 6-31G (d) and 6-31+G (d) basis sets for main group elements to calculate polarisability and first hyperpolarisability. The second-order polarisability of the system is significantly enhanced by replacing NH2 or NO2 with hexamolybdate in [NO2-HBC(derivative of hexabenzocoronene)-NH2] from 33.33x10(-30) esu (system 1) to 57.71x10(-30) esu (system 2) and 231.10x10(-30) esu (system 3), respectively. The time-dependent density functional theory (TDDFT) calculations show that the charge transfer from polyanion to graphene in systems 2 and 3 is responsible for the NLO properties of this kind of compound. We believe that the novel designed link between graphene and POMs is a door for further studies to find materials with an excellent NLO response.