Control of third-order nonlinear optical properties by coordination metal change based on a series of metal organic chains

Abstract

The research on the third-order nonlinear optics (NLO) materials have attracted more and more attention. In this work, an organic ligand (H2L) containing azo phenyl group and coordination N atom is selected. The presence of NN increases the fluidity of electrons in the azo molecule, which greatly improves the third-order nonlinearity. Furthermore, we synthesized three H2L-based metal complexes [Mn(L)(H2O)4]n (1), [Zn(L)(H2O)2]n (2) and [Cd(L)(H2O)4]n (3) and their nonlinear performances was also measured using Z-scan technology. The results show that the coordination bond between metal ions and the ligand changes the delocalization of the whole systems, resulting in changed the nonlinear performances. The calculation of density functional theory (DFT) confirms that the Mn2+ and Zn2+ addition is not obvious to influence NLO, and the addition of Cd2+ makes the non-linear signal weaken. The reason may result from the valence layer electron configuration of the different metal ions.