Supramolecular Third-order Nonlinear Optical Switches based on the Photo-Controllable Assemblies of Phthalocyanines

摘要

It is well known that the third-order nonlinear optical (3rd NLO) properties of phthalocyanines (Pcs) depend not only on the chemical structure of component monomers, but also on their packing arrangement, which provides the possibility to incorporate switchablity into the 3rd NLO behavior of such materials at supramolecular level. Herein, we rationally designed three kinds of novel photochromic moiety containing Pcs. By utilizing the photo-induced changes in the geometry and electronic delocalization distributions of photochromic moieties under the alternative illumination of suitable UV and visible light, the self-assemblies of Pcs were successfully photo-controlled in an efficient manner. As a consequence, a series of supramolecular 3rd NLO switching materials was obtained. All these materials showed very apparent difference in molecular second hyperpolarizabilities between “on” and “off”states. Besides, they also showed large molecular second hyperpolarizabilities at the order of 10-30 esu both in “on” and “off” states. All the results suggest that these materials are potential in emerging optoelectronics and photonic technologies.