A new electrophosphorescent material, iridium(III)tris(5-(2,4-difluoro-phenyl)-10,10- dimethyl-4-aza-tricycloundeca-2,4,6-triene), Ir(F2-mppy)3, has been synthesized and characterized. Ir(F2-mppy)3 shows strong blue emission peaking at 475nm with a high phosphorescent quantum yield (ΦPL) of 0.72 in degassed toluene. Electroluminescent devices with a structure of indium tin oxide (ITO)/NPB (40nm)∕Ir(F2-mppy)3(x):CBP (30nm)/BCP (6nm)∕Alq3 (20nm)∕Mg:Ag (10:1) and 15% (10%) exhibit a maximum luminous power efficiency of 9.58lm∕W (7.68lm∕W), CIE coordinates (x=0.18,y=0.36) (x=0.17,y=0.29), and a maximum luminance of ∼9000cd∕m2 at 12.5V (∼6000cd∕m2 at 11.5V).

We demonstrated an organic red-light-emitting device (ORLED) using a host, 5,6-bis-[4-(naphthalene-1-yl-phenyl-amino)-phenyl]-pyrazine-2,3-dicarbonitrile (BNPPDC), and a dopant, 2,3-bis[[[(2-hydroxy-4-diethylamino)phenyl] (methylene)] amino]-2-butanedinitrile (BDPMB). The device achieved a brightness of 9730cd∕m2 at a 11V, a power efficiency of 2.35lm∕W, a current efficiency of 3.36cd∕A at 4.5V, and a low turn-on voltage of 3.0V, with nearly saturated red emission. The device is superior or equal to the best fluorescent ORLEDs reported. BNPPDC generally induced a significant blueshift in dopant emission, thus it may serve as a host for dopants emitting at long wavelengths in ORLEDs with improved performance.

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We report the fabrication of high-efficiency white organic light-emitting devices (WOLEDs) by using a blue phosphorescent dye iridium (III) tris(5-(2,4-difluoro-phenyl)-10,10-dimethyl- 4-aza-tricycloundeca-2,4,6-triene) (Ir(F2-mppy)3) to sensitize the red dye[2-methyl-6- [2-(2,3,6,7-tetrahydro-1H c5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene]propane-din- itrile (DCM2). Ir(F2-mppy)3 and DCM2 were codoped into the 4,4′-N,N′-dicarbazole-biphenyl (CBP) host. The WOLEDs with 8wt% Ir(F2-mppy)3 and 0.5wt% DCM2 showed white emission with a color rendering index of 70. The maximum luminance and maximum current efficiency of the device are, respectively, 16220cd∕m2 and 9.28cd∕A.

We report polymeric light-emitting diodes (PLEDs) made from pinene-substituted iridium(III) phosphorescent dopants: tris(5-(4-difluoro phenyl)-10,10-dimethyl-4-aza-tricycloundeca-2,4,6-triene) iridium (III) [Ir(F-pppy)3] and tris(5-(2,4-difluorophenyl)-10,10-dimethyl-4-aza-tricycloundeca-2,4,6-triene) iridium (III) [Ir(F2-pppy)3]. The pinene substitution introduces steric hindrance to molecular structure of the dopant that reduces triplet-triplet annihilation between dopants and consequently enhances device performance. Via endothermic energy transfer from poly(vinylcarbazole) to Ir(F-pppy)3 and Ir(F2-pppy)3, a peak electroluminescent efficiency of 32.8cd∕A or 12.3cd∕A at 12wt% Ir(F-pppy)3 or 15wt% Ir(F2-pppy)3 doped and solution-processed PLEDs have been obtained. These values represent significant improvement in performance over previously reported endothermic energy-transfer based electrophosphorescent devices.