| Development of organic electrophosphorescent materials and their light-emittingdevices were reviewed in this dissertation. To solve the problems of low-efficiencyemission and imbalanced changre injection for electrophosphorescent materials, wehave designed and synthesized a class of cyclometalated iridium (III) and platinum (IIcomplexes with both oxadiazole and carbazole functional groups, and haveinvestigated their luminescence properties. The key studies results are listed below:(1) Ancillary ligands of picolinic acid derivative containing carbazole moiety andcyclometalated ligands of 2,4-diflurophenylpyridine derivatives containing oxadiazolemoiety were synthesized.(2) The bipolar cyclometalated iridium (III) and platinum (II) complexescontaining oxadiazole and carbazole groups were prepared. The results indicate thatthese cyclometalated complexes display intense UV-absorption and photo-luminescence properties. The UV absorption peaks around 380 nm and 345 nm frommetal-to-ligand charge transfer (MLCT) transition, as well as the emission peaks at476 nm and 480 nm are observed for the iridium complexes and platinum complexesin dichloromethane, respectively. Owing to alkoxy chain nonconjugated connectionbetween functional groups and ligands, cyclometalated iridium (III) and platinum (II)complexes exhibited minor photoluminescent spectral change.(3) The phosphorescent polymer light-emitting devices (PLEDs) using(t-Bu-OXDdfppy)Pt(pic-Cz) as guest and a blend of poly (N-vinylCarbazole) (PVK)and 2-(4-tert-butylphenyl)-5-biphenyl-1,3,4-oxadiazole (PBD) as host matrix werefabricated. The influence of molecular structures and dopant concentrations onelectroluminescence of the platinum (II) complexes has been investigated. Thephosphorescent PLEDs exhibite the maximum luminance of 360 cd/cm~2.(4) This work has a good foundation for studying blue electrophosphorescentmaterials and gaining new bipolar-transporting electrophosphorescent materials withexcellent luminescent properties.
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