Highly thermally stable binary cross-linkable organic nonlinear optical materials based on different Diels-Alder or Huisgen cycloaddition reaction

Abstract

The development of binary crosslink-able electro-optical materials with 100wt% chromophore which possess ultrahigh electro-optic coefficient and high long term alignment stability has been a crucial goal. Anthracene-maleimide and Maleimide-furan-based Diels–Alder (DA) reaction and Azide−alkyne-based Huisgen cycloaddition reaction has been developed for making highly efficient binary crosslink-able tetrahydroquinoline based chromophores QLD1 and QLD3-QLD6. Polymer cross-linked network was formed by these three reactions at different temperatures after electric field poling orientation, which greatly improving the stability of the materials. Electro-optic coefficient up to 234-312 pm/V and glass transition temperature as high as 118-160 ℃ was achieved in these cross-linked film due to high chromophore density (5.24 - 5.71 × 1020 molecules/cm3) and large hyperpolarizability. Long-term and high-temperature stability tests showed that after heating at 85 °C for over 500 h, 93.45%-95.13% of the initial r33 value was maintained for poled and crosslinked electro-optic films 2:1 QLD5 QLD6 and 1:1 QLD1/ QLD3. These results provide a very effective molecular engineering approach to systematically design binary cross-linked electro-optical materials for high performance device applications.