Synthesis of chromophores with ultrahigh electro-optic activity: Rational combination of the bridge, donor and acceptor groups

Abstract

A series of high performance chromophores P1P3, based on N-(4-dibutylaminophenyl) tetrahydroquinolinyl or julolidinyl donors, and phenyl-trifluoromethyl-tricyanofuran acceptors linked together via π-conjugation through thiophene or vinylene moieties as the bridges, have been designed and synthesized. Density functional theory (DFT) was used to calculate the HOMO-LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. Chromophores P1 and P3 had good thermal stabilities with glass transition temperature higher than 110 °C. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers with rational chromophore designs. In electro-optic activities, the poled films of P1/APC, P2/APC and P3/APC afforded r33 values of 223, 283 and 278 pmV−1, respectively, at 1310 nm at the doping concentration of 25 wt%, which showed significant enhancement over the similar EO polymer systems previously reported.