Introduction of fluorine to change the dielectric environment of nonlinear optical chromophores for improved electro-optic activities

Abstract

Fluorine was non-conjugatedly linked to the donor of nonlinear optical chromophore to investigate the effect of highly electronegative fluorine on intramolecular charge-transfer and electro-optic activities. 1HNMR spectra and UV–vis absorption were used to investigate that introduction of fluorine change the dielectric environment of intramolecular charge-transfer. Fluorinated chromophore showed more intensified absorption and its absorption properties was more stable to dielectric change in solution. In solid state of guest-host electro-optic polymer films, this dielectric environment stabilization was revealed to attenuate the dipole–dipole interactions of chromophores. Higher electro-optic coefficients (148pm/V) and higher chromophore loading density (30wt%) of fluorinated material chr-2/APC than benchmark material chr-1/APC (116pm/V at 25wt%) was achieved.