科研之友
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摘要
Increasing exciton utilization and reducing exciton annihilation are crucial to achieve high performance of organic light-emitting diodes (OLEDs), which greatly depend on molecular engineering of emitters and hosts. A novel luminogen (SBF-BP-DMAC) is synthesized and characterized. Its crystal and electronic structures, thermal stability, electrochemical behavior, carrier transport, photoluminescence, and electroluminescence are investigated. SBF-BP-DMAC exhibits enhanced photoluminescence and promotes delayed fluorescence in solid state and bipolar carrier transport ability, and thus holds multifunctionality of emitter and host for OLEDs. Using SBF-BP-DMAC as an emitter, the nondoped OLEDs exhibit maximum electroluminescence (EL) efficiencies of 67.2 cd A(-1), 65.9 lm W-1, and 20.1%, and the doped OLEDs provide maximum EL efficiencies of 79.1 cd A(-1), 70.7 lm W-1, and 24.5%. A representative orange phosphor, Ir(tptpy)(2)acac, is doped into SBF-BP-DMAC for OLED fabrication, giving rise to superior EL efficiencies of 88.0 cd A(-1), 108.0 lm W-1, and 26.8% for orange phosphorescent OLEDs, and forward-viewing EL efficiencies of 69.3 cd A(-1), 45.8 lm W-1, and 21.0% for two-color hybrid warm-white OLEDs. All of these OLEDs can retain high EL efficiencies at high luminance, with very small efficiency roll-offs. The outstanding EL performance demonstrates the great potentials of SBF-BP-DMAC in practical display and lighting devices.
