RESUMEN
The development of electro-optical materials with high chromophore loading levels that possess ultrahigh electro-optic coefficients and high long term alignment stability is a challenging topic. Anthracene-maleimide Diels-Alder (DA) reaction and π-π interaction of Anthracene-pentafluorobenzene and benzene-pentafluorobenzene are developed for making highly efficient binary cross-linkable/self-assembled dendritic chromophores FZL1-FZL4. A covalently or non-covalently cross-linked network is formed by DA reaction or π-π interaction after electric field poling orientation, which greatly improves the long-term alignment stability of the materials. An electro-optic coefficient up to 266 pm V-1 and glass transition temperature as high as 178 °C are achieved in cross-linked film FZL1/FZL2, and 272-308 pm V-1 is achieved for self-assembled films FZL1/FZL4 and FZL3/FZL4 due to high chromophore density (3.09-4.02 × 1020 molecules cm-3 ). Long-term alignment stability tests show that after heating at 85 °C for over 500 h, 99.73% of the initial r33 value is maintained for poled crosslinked electro-optic films 1:1 FZL1/FZL2. The poled self-assembled electro-optic films 1:1 FZL1/FZL4 and 1:1 FZL3/FZL4 can still maintain more than 97.11% and 98.23%, respectively, of the original electro-optic coefficient after being placed at room temperature for 500 h. The excellent electro-optic coefficient and stability of the material indicate the practical application prospects of organic electro-optic materials.
RESUMEN
A series of novel chromophores A, B, C, and D, based on the julolidinyl donor and the tricyanofuran (TCF) and CF3-tricyanofuran (CF3-Ph-TCF) acceptors, have been synthesized and systematically investigated. The 3,5-bis(trifluoromethyl)benzene derivative isolation group was introduced into the bridge in the chromophores C and D. These nonlinear optical chromophores showed good thermal stability, and their decomposition temperatures were all above 220 °C. Density functional theory (DFT) was used to calculate the energy gaps and first-order hyperpolarizability (ß). The macroscopic electro-optic (EO) activity was measured using a simple reflection method. The highest EO coefficient of poled films containing 35 wt% of chromophore D doped in amorphous polycarbonate afforded values of 54 pm/V at 1310 nm. The results indicate that the 3,5-bis(trifluoromethyl)benzene isolation group can suppress the dipole-dipole interaction of chromophores. The moderate r33 value, good thermal stability, and good yield of chromophores suggest their potential use in the nonlinear optical area.
RESUMEN
A new fluorinated polycarbonate was synthesized by solution polymerization of bisphenol AF, anthracen-9-ylmethyl-4,4-bis(4-hydroxyphenyl)pentanoate with triphosgene. This new polycarbonate was used as a host polymer. A traditional chromophore with a D-π-A structure was modified by bisphenol A acrylate affording chromophore A. The large modified group can not only effectively avoid the dipole interaction between chromophores, but also endow the chromophores with the properties of attaching and crosslinking with a host polymer through in situ Diels-Alder "click chemistry" reactions. Such properties can improve both the poling efficiency and the thermal stability of organic electro-optic (EO) polymers. The thermodynamic properties of the crosslinking system showed that the glass transition temperature rose with the increase of the chromophore content. The EO polymer showed a large EO coefficient of about 78.9 pm V-1 at a wavelength of 1310 nm and an excellent long-term stability of about 89% with respect to its initial value and it can be kept after 300 h of heating at 80 °C.