Synthesis, characterization and third-order nonlinear optical properties of novel hyperbranched donor-acceptor polyfluorenes based on 1,3,6,8-tertsubstituted carbazole core

Two novel hyperbranched donor-acceptor polyfluorenes based on 1,3,6,8-tertsubstituted carbazole core (4BrCzP1 and 4BrCzP2) were synthesized and characterized. The third order nonlinear optical properties of the materials were studied using Z-scan technique with femtosecond Ti: sapphire laser with delivering pulses of 140 fs at 800 nm. The nonlinear optical refractive index was 9.29 × 10−8 esu for 4BrCzP1 and 3.19 × 10−7 esu for 4BrCzP2, respectively. While the third order nonlinear susceptibility was 1.29 × 10−9 esu for 4BrCzP1 and 4.33 × 10−9 esu for 4BrCzP2, respectively. The experimental results indicated that the hyperbranched polyfluorenes was a promising candidate in the application of third order nonlinear optical materials.