Designs And Syntheses Of Conjugated Polymers Based On Fluorene & Studies On Their Light-Emitting Properties

Compared with small molecule organic molecule electroluminescent devices, polymer light-emitting diodes have attracted much interests all over the world because of their easily fabrication, good thermal stability, high photoluminescence quantum efficiency and good processablity. In this dissertation, the development of polymer light-emitting materials is reviewed, especially for polyfluorenes. To overcome the defects of polyfluorenes, a series of new PF derivatives with alkyl or alkyloxybiphenyl groups at the 9-position of fluorene were designed and synthesized by Yamamato coupling reaction. Moreover, the copolymers containing thiophene based on the homopolymers synthesized above were prepared. Their thermal stability, photoluminescence and the relationship between polymer structure and luminescent property were also studied.The research results indicated that all of the polymers possess excellent solubility and film-forming property as well as intense fluorescence in both solid states and solution. Comparaed with the other PFs, polyfluorenes with biphenyl side chains possess more satisfactory thermal stabilities and high glass transition temperature. Meanwhile, the incorporation of biphenyl side chains can effectively suppress the formation of aggregates and excimers, resulted in the improvement of the purity and stability of polyfluorene's emitting light, and the extratorsion between the fluorine units is not been found.