Synthesis and characterization of red-emission PPV copolymers containing fluorenone unit

Two soluble copolymers of fluorenone and dioctoxylbenzene (PFN) or anthracene (PFNAn) were synthesized through Heck polymerization, and were characterized by gel permeation chromatography (GPC), FT-IR, 1H-NMR, elemental analysis and thermogravimetric analysis. The polymers possess good solubility in common organic solvents and high thermal stability with the onset decomposition temperature at higher than 410 °C. The photophysical properties of the polymers were investigated in both solutions and spin-coated films. Cyclic voltammetry results revealed that the copolymers possess higher electron affinity and reversible reduction/re-oxidation processes. Their electroluminescent properties were further investigated. PFN and PFNAn show stable and saturated red light emission with high thermal stability and high electron injection ability. This type of conjugated polymers may be promising for the applications as electron acceptors in polymer photovoltaic cells and electron transporting materials.