Abstract:

Poly(9-substituted fluorenylidene-phenylene)s were synthesized with Suzuki cross-coupling reaction using different Pd catalyst in order to develop new organic materials used in organic light-emitting field-effect transistors. The polymers were soluble in common organic solvents. The studies of DSC, X-ray diffraction and polarizing optical microscope(POM) show that the polymers are enantiotropic liquid crystal and form Nematic phase. It is found that the polymers prepared with different Pd catalysts have the similar molecular weights. The kind of catalysts has a great impact on the stereoregularity of the polymer main chain, mesophase as well as optical properties of the polymers. The polymer prepared by Pd(PPh₃)₄ has higher stereoregularity, wider mesophase ranges, higher fluorescence qutum yield and better optical properties.

Key words: Fluorenylidene, Liquid crystalline conjugated polymer, Organic light-emitting field-effect transistor