Designs And Syntheses Of Novel Polyfluorene Derivatives & Studies On Their EL Properties

Compared with small molecule organic electroluminescent devices. Polymer light-emitting diodes have attracted much interest all over the world because of their easily fabrication, high photoluminescence quantum efficiency, good thermal stability and good processability. In this dissertation, the development of polymer electroluminescent materials and their applications in polymer Light-emitting diode (PLED) are reviewed, especially polyfluorence derivatives and their devices. Four types of novel copolymers containing imidazole, benzothiazole and pyrazo- line, benzothiazolylpyrazoline and thiophene and 2-pyran-4-ylidene-malononitrile units based on fluorene were designed and synthesized, and were used to fabricate PLED for the first time. Their thermal stability, photoluminescence(PL), electro- luminescence(EL), and the relationship between structure and properties were also studied.The DSC and TGA results indicated that all of the copolymers possess satisfactory thermal stabilities. As to their PL properties, all these materials exhibit good fluorescence in both solid states and solution. Furthermore they possess excellent solubility and film-forming property. The EL results indicated that the copolymers can be used as emitting materials to fabricate the PLEDs that can emit red, green and blue lights. They have excellent EL properties and are considered to be new prospective EL materials.