Enhancement of electroluminescence utilizing confined energy transfer for red light emission

Ohmori, Yutaka; Kajii, Hirotake; Sawatani, Takumi; Ueta, Hiroyasu; Yoshino, Katsumi

doi:10.1016/s0040-6090(01)01128-2

Cited by 95 publications

(45 citation statements)

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“…Figure 6 shows the HOMO and LUMO energy levels of these DCM derivatives, along with those of PVK, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), tris(4-(2-phenylethynyl)-phenyl)amine (TPA), tris(8-quinolinolato) aluminum (Alq 3 ) (see Scheme 4 for their chemical structures), indium tin oxide (ITO), and LiF:Al, which were utilized to fabricate the electroluminescent devices (see below). The data for PVK, [26] BCP, [27] Alq 3 , [28] ITO, [15] and LiF:Al [15] are cited from the literature, while those of TPA were calculated from the onset oxidation potential and absorption edge measured in this work.…”

Section: Homo and Lumo Levelsmentioning

confidence: 99%

“…Interestingly, the performance of the MBIN-based electroluminescent device can be improved dramatically by co-doping. [32][33][34][35][36] Table 2, respectively. Compared with device IV, the co-doping of TPA gave rise to a decrease in the turn-on voltage, from 6.2 to 5.1 V; an increase in the maximum luminance, from 2934 (at 15 V) to 6791 cd m -2 (at 16.5 V); an enhancement in the maximum current efficiency, from 3.13 (132 cd m -2 ) to 6.14 cd A -1 (405 cd m -2 ); and a shift in the CIE coordinates, from (0.65,0.35) to (0.66,0.33).…”

Section: Full Papermentioning

confidence: 99%

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Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

et al. 2006

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Three new starburst DCM (4‐(dicyanomethylene)‐2‐methyl‐6‐[4‐(dimethylaminostyryl)‐4H‐pyran]) derivatives, 4,4′,4′′‐tris[2‐(4‐dicyanomethylene‐6‐t‐butyl‐4H‐pyran‐2‐yl)‐ethylene]triphenylamine (TDCM), 4,4′,′′‐tris[2‐(4‐(1′,3′‐indandione)‐6‐t‐butyl‐4H‐pyran‐2‐yl)‐ethylene]triphenylamine (TIN), and 4‐methoxy‐4′,4′′‐bis[2‐(4‐(1′,3′‐indandione)‐6‐t‐butyl‐4H‐pyran‐2‐yl)‐ethylene]triphenylamine (MBIN), have been designed and synthesized for application as red‐light emitters in organic light‐emitting diodes (OLEDs). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) reveal their extremely high glass‐transition temperatures and decomposition temperatures, as well as their low tendency to crystallize. Photoluminescence and electroluminescence measurements show that they exhibit a greatly restricted concentration‐quenching effect compared to DCM1 (4‐(dicyanomethylene)‐2‐methyl‐6‐[p‐(N,N‐dimethylamino)‐styryl]‐4H‐pyran), a simple but typical DCM‐type dye, as a result of their non‐planar, three‐dimensional structures that result from their unique propeller‐like triphenylamine electron‐donating cores. The peripheral electron‐withdrawing moieties also play a key role in the restriction of concentration quenching. That is, TIN and MBIN, bearing 1,3‐indandione acceptors, emit more efficiently than TDCM and DCM1, which have dicyanomethylene as acceptors at a high doping concentration of 10 wt.‐% in poly(9‐vinylcarbazole) (PVK) film, irrespective of whether they are photoexcited or electroexcited, though their fluorescence quantum yields in dilute solutions are much lower than that of DCM1. By way of the co‐doping approach, the electroluminescence device with the configuration indium tin oxide (ITO)/PVK:MBIN(10 wt.‐%):tris(4‐(2‐phenylethynyl)‐phenyl)amine (TPA; 30 wt.‐%) (70 nm)/2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline (BCP; 20 nm)/tris(8‐quinolinolato) aluminum (Alq3;15 nm)/LiF (0.3 nm)/Al (150 nm) exhibits a turn‐on voltage of 5.1 V, a maximum luminance of 6971 cd m–2, a maximum efficiency of 6.14 cd A–1 (405 cd m–2), and chromaticity coordinates of (0.66,0.33). The encouraging electroluminescence performance suggests potential applications of the starburst DCM red‐light emitters in OLEDs.

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Section: Homo and Lumo Levelsmentioning

confidence: 99%

Section: Full Papermentioning

confidence: 99%

Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

et al. 2006

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“…[1][2][3][4][5][6][7][8] However, for many reasons the electroluminescence (EL) performance of these lanthanide materials is still much lower than what people expect. The unbalanced hole and electron injection and transport should be one of the most important factors.…”

Section: Introductionmentioning

confidence: 99%

Highly Improved Electroluminescence from a Series of Novel Eu^III Complexes with Functional Single‐Coordinate Phosphine Oxide Ligands: Tuning the Intramolecular Energy Transfer, Morphology, and Carrier Injection Ability of the Complexes

Yin

Huang

2007

Chemistry A European J

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The functional single-coordinate phosphine oxide ligands (4-diphenylaminophenyl)diphenylphosphine oxide (TAPO), (4-naphthalen-1-yl-phenylaminophenyl)diphenylphosphine oxide (NaDAPO), and 9-[4-(diphenylphosphinoyl)phenyl]-9H-carbazole (CPPO), as the direct combinations of hole-transporting moieties, and electron-transporting triphenylphosphine oxide (TPPO) were designed and synthesized (amines or carbazole), together with their Eu(III) complexes [Eu(tapo)(2)(tta)(3)] (1), [Eu(nadapo)(2)(tta)(3)] (2), and [Eu(cppo)(2)(tta)(3)] (3; TTA: 2-thenoyltrifluoroacetonate). The investigation indicated that by taking advantage of the modification inertia of the phosphine oxide ligands, the direct introduction of the hole-transport groups as chromophore made TAPO, NaDAPO, and CPPO obtain the most compact structure and mezzo S(1) and T(1) energy levels, which improved the intramolecular energy transfer in their Eu(III) complexes. The amorphous phase of 1-3 proved the weak intermolecular interaction, which resulted in extraordinarily low self-quenching of the complexes. The excellent double-carrier transport ability of the ligands was studied with Gaussian calculations, and the bipolar structure of TAPO and CPPO was proved. The great improvement of the double-carrier transport ability of 1-3 was shown by cyclic voltammetry. Their HOMO and LUMO energy levels of around 5.3 and 3.0 eV, respectively, are the best results for Eu(III) complexes reported so far. A single-layer organic light-emitting diode of 2 had the impressive brightness of 59 cd m(-2) which, to the best of our knowledge, is the highest reported so far. Both of the four-layer devices based on pure 1 and 2 had a maximum brightness of more than 1000 cd m(-2), turn-on voltages lower than 5 V, maximum external quantum yields of more than 3 % and excellent spectral stability.

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“…In these devices, large contact area between the donor and acceptor such as (6,6)-phenyl C61-butyric acid methyl ester leads to efficient exciton dissociation and high power conversion efficiency(PCE) [1,2] . Meanwhile, polythiophene derivatives are mostly used as donor materials [3] .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of poly (N-Hexyl-2, 7-di(2-(4-hexylthiophene)carbazole)

Yong

Liu

et al. 2015

J. Wuhan Univ. Technol.-Mat. Sci. Edit.

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One conjugated polymer consisting of carbazole and 3-hexylthiophene moiety, poly (N-Hexyl-2,7-di(2-(4-hexylthiophene)carbazole) (PNDC), has been synthesized by ferric chloride oxidative polymerization. The monomer N-Hexyl-2,7-di(2-(4-hexylthiophene)carbazole was synthesized and characterized by IR, 1 H-NMR, 13 C-NMR and MS. UV-vis absorption spectrum, fluorescence spectrum, photoluminescence spectrum and electrochemical properties of the polymer were investigated. Polymer PNDC shows maximum peak appearing at 394 nm in UV-vis absorption spectrum, strongest fluorescence-emission at 482 nm in fluorescence spectrum and maximum emission peak at 492 nm in photoluminescence spectrum. The band-gap (E g ), HOMO energy (E HOMO ), and LUMO energy (E LUMO ) of the polymer were obtained as 2.58, -5.32, and -2.74 eV, respectively.

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Enhancement of electroluminescence utilizing confined energy transfer for red light emission

Cited by 95 publications

References 2 publications

Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

Highly Improved Electroluminescence from a Series of Novel Eu^III Complexes with Functional Single‐Coordinate Phosphine Oxide Ligands: Tuning the Intramolecular Energy Transfer, Morphology, and Carrier Injection Ability of the Complexes

Synthesis and characterization of poly (N-Hexyl-2, 7-di(2-(4-hexylthiophene)carbazole)

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Enhancement of electroluminescence utilizing confined energy transfer for red light emission

Cited by 95 publications

References 2 publications

Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

Highly Improved Electroluminescence from a Series of Novel EuIII Complexes with Functional Single‐Coordinate Phosphine Oxide Ligands: Tuning the Intramolecular Energy Transfer, Morphology, and Carrier Injection Ability of the Complexes

Synthesis and characterization of poly (N-Hexyl-2, 7-di(2-(4-hexylthiophene)carbazole)

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Highly Improved Electroluminescence from a Series of Novel Eu^III Complexes with Functional Single‐Coordinate Phosphine Oxide Ligands: Tuning the Intramolecular Energy Transfer, Morphology, and Carrier Injection Ability of the Complexes