Enhanced electro-optic coefficient (r33) in nonlinear optical chromospheres with novel donor structure

The synthesis and characterization of new push-pull chromophores A and B, from tricyanofuran (TCF) electron withdrawing and various electron donating moieties, have been demonstrated to compare the roles of donors in electro-optic performance. The crystal structure analyses of the intramolecular hydrogen bond, molecular coplanarity and π–π interactions reveal that A forms cross-stacking, while B forms antiparallel dimer packing, which indicates weaker intermolecular interactions of A than B. Also, the photophysical properties, solvatochromic behavior and Density Functional Theory (DFT) calculations were also investigated. In electro-optic activities, the doped films-A containing chromophore A display an r33 value of 36 pm V−1 at the saturated doping concentration of 40 wt%, while the doped films-B containing B show a maximum r33 value of 16 pm V−1 at the saturated concentration of 25 wt%. High loading density and high r33 value indicate that the chromophore A with julolidinyl-based donor can efficiently reduce the interchromophore electrostatic interactions and enhance the macroscopic optical nonlinearity, showing that chromophore A with julolidinyl-based donor has promising applications in nonlinear optical (NLO) materials.