Strong nonlinear optical response in star-shaped push–pull triphenylamine derivatives

The nonlinear optical (NLO) properties of the triphenylamine-based star-shaped (A-π-)₃D (A) and star-shaped (D-A-π-)₃D (B) derivatives are investigated by Z-scan, spatial self-phase modulation, and white light interferometry technology. Both chromophores possessed excellent NLO properties, the measured nonlinear absorption coefficient and nonlinear refractive index in both chromophores are much higher than previously reported. Especially, B has more remarkable NLO effects. The results indicate that the star-shaped triphenylamine derivatives with push–pull systems exhibited excellent NLO properties, by introducing functional groups such as pentafluorobenzene and N,N-dimethyl with different electron donating or electron withdrawing behaviors to adjust the electronic structure of the chromophore, the NLO effects of organic molecules can be greatly improved. The light modulation refractive index changes of B are also larger than A, once again indicate that the NLO effects could be enhanced by tuning the conjugated organic molecules as chromophores.