Optimization across-the-Board: Centro-Arylated Push-Pull Tetraene Chromophores and Guest-Host Polymers for Electro-Optics.

Abstract

The research and development of push-pull tetraene chromophores (PPT-phores) have contributed greatly to the field of organic electro-optic (EO) materials and devices since the inauguration of CLD-1 in 2001. This study is thus a systematic contribution to synthesize and characterize a series of centro-arylated PPT-phores based on strong electron-donating tetrahydroquinolinyl groups and variable strong electron-accepting tricyanofuran derivatives. In particular, we report the crystallographic data to show various packing modes of these PPT-phores with detailed information about bond length alternation and intermolecular interactions, the optical absorption edges of guest-host polymers by the Tauc model, and the anisotropy and dispersion of Pockels tensors for the poled polymers by attenuated total reflection spectroscopy. Such analyses have not been addressed to any significant extent previously and are fundamentally important to the future development of PPT-phore-based EO materials and devices. The poled films of several centro-arylated PPT-phores in polycarbonates exhibited large EO activities, excellent thermal stability, and tunable optical transparency at the telecom O- and C-band. The study demonstrates the effectiveness of π-bridge centro-arylation enabled by molecular shape modification and rigidity enhancement, over the relatively flexible and labile thioether or alkoxy groups, in rational design of hyperpolarizable PPT-phores for high-performance EO polymers.