Synthesis And Properties Of Pt-Pt And Ir-Ir Cyclometalated Complexes Based On Oxadiazole And Indolo[3,2-b]carbazole

The work describes the development of white organic/polymeric light-emittingdevices （WOLEDs/WPLEDs）. In order to solve a series of problems, such as a few ofsingle organic molecules with white emission, concentration quenching, poor deviceperformance in WOLEDs/WPLEDs, we designed and synthesized a class of dinuclearcyclometalated platinum-platinum complexes with a bridged oxadiazole derivativeand another class of dinuclear cyclometalated iridium/platinum complexes with thebridged indolo[3,2-b] carbazole derivative. Their structures were characterized by1HNMR,13C NMR, MALDI-TOF MS and elemental analysis. Their thermal, opto-physical properties were investigated at the same time. A series of single-doped andsingle-emission-layer （SEL）-based polymer light-emitting devices （PLEDs） weremade. The influences of the bridged groups, as well as the functionalized groups ofoxadiazole and triphenylamine on the electroluminescent properties were studied.Two novel kinds of the single white-emitting organic phosphor materials wereobtained. The key results are listed below:1. Dinuclear cyclometalated platinum-platinum complex of （C₈dfppy）₂Pt₂（dipic-OXD） with the bridged oxadiazole derivative was designed and synthesized.Compared to the mononuclear platinum complex of （C₈dfppy）Pt（pic）, this dinuclearplatinum complex exhibited a new and enhanced UV-absorption peak at326nm in itsDCM solution and weaker excimer/aggregate emissions in its neat film. The（C₈dfppy）₂Pt₂（dipic-OXD）-doped devices displayed more stable EL spectra at thedopant concentrations from1%to8%. The aggregation/excimer emission was effec-tively suppressed. Under non-optimal condition, the maximum luminance of411cd/m²was obtained and the current efficiency was effectively enhanced.2. Six kinds of novel dinuclear cyclometalated iridium/platinum complexes weredesigned and synthesized, which contains2,4-difluorophenylpyridine cyclometalatedligand and a bridged triphenylamine-substituted or oxadiazole-substituted indolo[3,2-b] carbazole derivative acted as the blue fluorophore group. When the dopantconcentrations were increased from1%to2%, the （dfppy）₂Pt₂（dipic-C₈ICZ）-,（dfppy）₂Pt₂（dipic-TPAICZ）-and （dfppy）₂Pt₂（dipic-tBuOXDICZ）-doped devices dis-played a near-white emission, but an orange emission while the dopant concentrationrose to8%. Among them, the （dfppy）₂Pt₂（dipic-TPAICZ）-doped devices displayedstable-white emission with a CIE （0.33,0.35） which is very close to white light （0.33,0.33） and maximum luminance of209cd/m²at the dopant concentration at1%. However, the corresponding dinuclear cyclometalated iridium complexes-dopeddevices only displayed its intrinsic emission.