Abstract
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 33.33 × 10− 30 esu (system 1) to 57.71 × 10− 30 esu (system 2) and 231.10 × 10− 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.
Acknowledgements
The authors gratefully acknowledge financial support by NSFC (20971020, 21073030 and 21131001), Program for New Century Excellent Talents in University (NCET-10-318), Doctoral Fund of Ministry of Education of China (20100043120007) and the Science and Technology Development Planning of Jilin Province (20100104).