Changing the shape of chromophores from “H-type” to “star-type”: increasing the macroscopic NLO effects by a large degree

Abstract

In this paper, an NLO polymer P2, consisting of “star-type” chromophore, was first prepared through the Suzuki coupling reaction and the Sonogashira coupling reaction. For comparison, its “H-shape” analogue P1, only consisting of an “H-type” chromophore, was synthesized. To further enhance the NLO coefficient and stability, the “star-type” chromophore was also introduced into hyperbranched polymer to yield P3. All of these polymers were soluble in polar organic solvents and well characterized. Due to the better topological structure and site isolation effect of “star-type” chromophore, the d₃₃ value of P2 was 1.8 times that of its “H-shape” analogue. The results confirmed that the “star-type” chromophore could reduce the intermolecular electrostatic interactions between chromophore moieties effectively, indicating the advantages of a “star-type” chromophore.