Synthesis and light-emitting properties of a fluorene containing hyperbranched conjugated poly(phenylene vinylene)

A novel fluorene containing hyperbranched conjugated poly(phenylene vinylene) (Hyper-PFPPV) was obtained through the Wittig polycondensation polymerization. Hyper-PFPPV has good solubility in common organic solvents and showed good thermal stability up to 369 degrees C with less than 5wt% weight loss. The photophysical properties of Hyper-PFPPV in solution and net solid film are inspected and compared with fluorene containing linear poly(1,4-phenylene vinylene) (PFPPV). An absorption maximum of Hyper-PFPPV film was determined at 385nm which was far blue shifted than that of linear PFPPV film (425nm). Hyper-PFPPV showed blue photoluminescence (PL) peak at 461nm. In addition, Hyper-PFPPV film exhibited almost no long wavelength emission peaks even the film was annealed at 80 degrees C for 1hr in air condition. High PL efficiencies (phi(sol) = 0.78 and phi(film) = 0.75) and no aggregate or excimer emission of Hyper-PFPPV are due to the inhibition of intramolecular or intermolecular interaction by the introduction of the hyperbranched network into the fluorene containing poly(phenylene vinylene) backbone.