Azobenzene-based derivative self-assembly: Optical limiting properties and enhancement mechanism

Abstract In order to further investigate the dependence of optical limiting properties on the molecular structures, especially the strong intermolecular effects, such as the effects of hydrogen bond, dipole-dipole interaction and the influences of their synergistic effect on the optical limiting properties, three polar D-π-A conjugated azobenzene derivatives (N1, N2 and N3) with different hydrogen-bond recognition abilities were designed and synthesized. Their molecular structure and properties were characterized and evaluated by infrared spectroscopy, thermogravimetric analysis, ultraviolet–visible spectrometry, and Z-scan technique with a Q-swithed ps Nd:YAG laser system continuum. The mechanism of optical limiting enhancement is investigated by theoretical calculation and experimental measurement based on molecular self-assembly synergistic effect of hydrogen bond and dipole-dipole interaction. The results show that the nonlinear optical properties of these polar D-π-A conjugated nonlinear optical materials were obviously affected by organic molecular structure, strong intermolecular interaction and their synergetic enhancement effect.