Achieving excellent electro-optic activity of chromophores by introducing a stronger electron donor and modifying the π-bridge

Abstract

We present here three chromophores with the same tricyanofuran acceptor, but with different donor moieties and bridges, synthesized by the conventional technique. Compared with chromophore without the substituted group, these modified chromophores show better stability. Structure analysis and photophysical properties were carried out to compare the molecular mobility and steric hindrance effect on chromophores. Density functional theory (DFT)was used to calculate the hyperpolarizability (β), and the results showed that the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic coefficients. By doping these chromophores with a high loading of 25 wt% in amorphous polycarbonate (APC), electro-optic (EO) coefficients (r33) of up to 163 pm V−1 at 1310 nm can be achieved. These results indicated that the introduced alkoxy group on the donor part or bridge part can enhance the donor ability and can also reduce intermolecular electrostatic interactions, thus enhancing the macroscopic electro-optic activity, which indicated that the structure–property relationship was essential.