ABSTRACT
Multilayered organic light-emitting diodes (OLEDs) were fabricated by using the new fluorine derivatives end-capped with arylaminofluorenylethylenes as dopant materials. The device structure was ITO/NPB/15% blue dopants doped in MADN/Bphen/Liq/Al. Among those, a device shows the maximum luminance of 40800 cd/m2 at 12 V, the luminous efficiency of 12.8 cd/A at 20 mA/cm2, power efficiency of 9.13 Im/W at 20 mA/cm2 and CIE(x,y) coordinates of (x = 0.188, y = 0.372) at 8 V.
Subject(s)
Ethylenes/chemistry , Fluorenes/chemistry , Fluorescent Dyes/chemistry , Lighting/instrumentation , Organic Chemicals/chemistry , Semiconductors , Color , Equipment Design , Equipment Failure AnalysisABSTRACT
We studied the use of N,N'-dicarbazolyl-3,5-benzene (mCP) of the triplet energy level 2.90 eV and p-bis(triphenylsilyly)benzene (UGH2) of the wide triplet energy band gap 3.50 eV as triplet exciton blocking layer (TEBL) to get high efficiency in phosphorescent blue organic light-emitting diodes. Five devices (Devices I-V) with different structures were fabricated to investigate the effect of mCP and UGH2 TEBLs on device performances. The maximum quantum efficiencies of devices I, II, III, IV and V were 5.10%, 1.41%, 5.90%, 4.98% and 0.61%, respectively.
ABSTRACT
The authors have demonstrated efficient and color-stable white organic light-emitting diodes (WOLEDs) by using three emitters, 4"-(2,2-diphenylvinyl)-1-[4-(N,N-diphenylamino)-styryl]-terphenyl (PVAS-tPh), fac tris(2-phenypyridine) irdium(III) (Ir(ppy)3), and Bis(5-benzoyl-2-phenylpyridinato-C,N)iridium(III) (acetylacetonate) (Bzppy)2Ir(III)acac). In this WOLEDs, 4,4'-N, N'-dicarbazole-biphenyl (CBP) were used as a spacer among three emitting layers. CBP between red and green emitting layers prevented the Commission Internationale de L'Eclairage (CIE(x,y)) coordinates change of white emission. As a result, WOLEDs showed a minimal change of deltaCIE(x,y) < (0.01,0.02) for the brightness change form 100 to 20 000 cd/m2.
ABSTRACT
Newly prepared hydrido iridium(III) complexes [Ir(ppy)(PPh3)2(H)L](0,+) (ppy = bidentate 2-phenylpyridinato anionic ligand; L = MeCN (1b), CO (1c), CN(-) (1d); H being trans to the nitrogen of ppy ligand) emit blue light at the emission lambda(max) (452-457, 483-487 nm) significantly shorter than those (468, 495 nm) of the chloro complex Ir(ppy)(PPh3)2(H)(Cl) (1a). Replacing ppy of 1a-d with F2ppy (2,4-difluoro-2-phenylpyridinato anion) and F2Meppy (2,4-difluoro-2-phenyl-m-methylpyridinato anion) brings further blue-shifts down to the emission lambda(max) at 439-441 and 465-467 nm with CIE color coordinates being x = 0.16 and y = 0.18-0.20 to display a deep-blue photoemission. No significant blue shift is observed by replacing PPh3 of 1a with PPh2Me to produce Ir(ppy)(PPh2Me)2(H)(Cl) (1aPPh 2Me), which displays emission lambda max at 467 and 494 nm. The chloro complexes, [Ir(ppy)(PPh3)2(Cl)(L)](0,+) (L = MeCN (2b), CO (2c), CN(-) (2d)) having a chlorine ligand trans to the nitrogen of ppy also emit deep-blue light at emission lambda(max) 452-457 and 482-487 nm.
