Rational enhancement of electro-optic activity:Design and synthesis of cyanoacetate containing nonlinear optical chromophores

Abstract We have developed three nonlinear optical chromophores A-C with the same diethylaminophenyl donor and tricyanovinyldihydrofuran acceptor coupled through isophorone bridge. The donor and bridge moiety of chromophores B and C are modified with functional group pentafluorobenzene and alkylaniline cyanoacetate (C1), respectively. In particular, the alkylaniline cyanoacetate group is not only a steric group, but also a short chromophore. Except for the steric effect, two C1 groups with considerable dipole moment will greatly weaken the electrostatic interaction between molecules by electrostatic screening effect before poling thus increasing the poling efficiency. Electro-optical films doped with chromophore A-C have been poled to give quite different r33 values of 69, 115 and 166 p.m./V at 1.31 μm, respectively. The normalized r33 value of chromphore C was up to 8.16 × 10−19 p.m. cc per (V molecules) which is more than four times higher than that of chromophore A without functional group.