Synthesis and properties of high efficiency light emitting hyperbranched conjugated polymers

A novel kind of hyperbranched conjugated light emitting polymers with 2,5-dimethyloxyl substituted phenylene vinylene as the connecting units and different hole or electron transporting groups such as dimethylaniline phenylene or pyridyl phenylene as the terminal groups were synthesized by modified one step Wittig polymerization reaction. The photophysical properties in solution and in films of hyperbranched conjugated polymers were studied in details. The oxidation potentials were measured by cyclic voltammetry. It was found that the hyperbranched conjugated polymers were highly soluble in common organic solvents, with good film-forming properties. In particular, the thermal stability of HPVs is extremely higher than that of linear polypherylene vinylene derivatives. In addition, the LED, LEC devices using hyperbranched polymer as active layer were investigated. All results show that these novel hyperbranched conjugated polymers could be good candidates for the fabrication of high performance LED and other optoelectronic devices. (C) 2002 Elsevier Science B.V. All rights reserved.