Theoretical investigation of second-order nonlinear optical response by linking hexamolybdate with graphene in the donor–acceptor (D–A) framework

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.

Keywords:

• polyoxometalate
• graphene
• second-order nonlinear optical property
• density functional theory

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).