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We have demonstrated efficient phosphorescent white organic light-emitting diodes (PHWOLEDs) by using iridium (III) bis(1-phenyl(quinolinato-N,C2′))acetylacetonate doped in 4,4,4-tris(N-carbazolyl)-triphenylamine as phosphorescent red emitting layer and iridium (III) bis[(4,6-di-fluoropheny)-pyridinato-N,C2] picolinate doped in dual blue-emitting layer (D-BEML), N,N′-dicarbazolyl-3,5-benzene and 2,2′,2″″-(1,3,5-benzenetryl) tris(1-phenyl)- 1H-benzimidazol, respectively. D-BEML structure have broad exciton formation zone than single BEML. The optimized PHWOLEDs showed an external quantum efficiency of 5.93%, current efficiency of 11.54 cd/A, and Commission Internationale de L’Eclairage coordinates of (0.45, 0.37) at 1000 cd/m2. [ABSTRACT FROM PUBLISHER]

The authors have demonstrated red organic light-emitting diodes (OLEDs) using a new fluorescent red emitter, 2-(2-(4-pentylbicyclo[2.2.2]octan-1-yl)-6-(2-(1,1,7-trimethyl-7-triphenysiliyllethyl-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-9-yl)vinyl)-4H-pyran-4-ylidene)malononitrile (DCJTPSO), achieved the maximum external quantum efficiency (EQE) of 2.06%, current efficiency (CE) of 3.83 cd/A, and Commision Internationale De L’Eclairage (CIEx,y) coordinates of (0.58, 0.40) at 0.029 mA/cm2 in comparison with control device using 4-(dicyanomethylene)-2-tert-butyl- 6-(1,1,7, 7-tetramethyljulolidin-4-yl-vinyl)- 4H-pyran which showed the maximum EQE of 1.07%, CE of 1.41 cd/A and CIEx,y coordinates of (0.61, 0.38) at 0.11 mA/cm2. This result showed that the high performance of red device using DCJTPSO showed easier electron trapping directly on the emitter molecule. [ABSTRACT FROM PUBLISHER]

We have demonstrated efficient deep-blue organic light emitting diodes using 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl (BCzVBi) doped in 4'-(dinaphthalen-2-yl)-1,1'-binaphthyl (DNBN) as emitting layer. There is more overlap between the photoluminescence (PL) spectrum of DNBN and ultra violet (UV)/visible absorption spectrum of BCzVBi than PL spectrum of 2-methyl-9,10-di(2-naphthyl) anthracene (MADN) and UV/visible absorption of BCzVBi, resulting in efficient energy transfer from DNBN to BCzVBi. The optimized deep-blue device showed a peak current efficiency of 5.12 cd/A, peak external quantum efficiency (EQE) of 4.72%, and as Commission Internationale d'Eclairage coordinates of (0.15, 0.12). The device using blue host, DNBN, exhibited higher EQE of 1.6 times at 1 mA/cm2 than control device using blue host, MADN. [ABSTRACT FROM AUTHOR]

In this paper, We have demonstrated lower driving voltage and efficient Blue phosphorescent organic light emitting diodes (PHOLEDs) using iridium (III) bis[(4,6-di-fluoropheny)-pyridinato-N,C2] picolinate doped in N,N'-dicarbazolyl-3,5-benzene (mCP) and 2,2',2''-(1,3,5-benzenetryl)tris(1-phenyl)-1H-benzimidazol (TPBi) as double-emitting layer system. D-EML layers were employed to have good exciton confinement. We also demonstrated that mCP as electron blocking layer inserted EML and HTL for higher efficiency. The optimized device of double EML of mCP:TPBi(1:1) exhibited a maximum external quantum efficiency of 9.22% at 0.21 mA/cm2, a maximum Current efficiency of 18.89 cd/A at 0.21 mA/cm2, and Commission Internationale de I'Eclairage coordinates of (0.17, 0.35) at 1000 cd/m2, respectively. [ABSTRACT FROM AUTHOR]

The naphthalene-based blue materials 4,4'-(Dinaphthalen-2-yl)-1,1'-binaphthyl (DNBN) and 1,4-(Dinaphthalen-2-yl)-naphthalene (DNN) were designed and synthesized for OLEDs. A device (non-doped) employing DNN as the emitter exhibited a maximum luminance, luminous efficiency, and external quantum efficiency of 1120 cd/m2, 1.40 cd/A, and 3.83%, respectively. Moreover, its CIE coordinates (0.152, 0.069) are very close to the NTSC blue standard of (0.14, 0.08). In order to improve EL efficiencies, these materials were used as the blue host materials for the blue dopants PFVtPh and PCVtPh. A device 1b (PFVtPh-doped) showed high EL efficiencies of 5.24 cd/A, 2.75 lm/W, and 3.82% at 20 mA/cm2. [ABSTRACT FROM AUTHOR]