Harvesting Excitons Via Two Parallel Channels for Efficient White Organic LEDs with Nearly 100% Internal Quantum Efficiency: Fabrication and Emission‐Mechanism Analysis

Wang, Qi; Ding, Junqiao; Ma, Dongge; Cheng, Yanxiang; Wang, Lixiang; Jing, Xiabin; Wang, Fosong

doi:10.1002/adfm.200800918

Cited by 394 publications

(215 citation statements)

References 84 publications

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“…Ma et al [ 206 ] doped both FIrpic (blue) and bis(2-(9,9-diethyl-9H-fluoren-2-yl)-1-phenyl-1H-benzoimidazol-N , C 3 ) iridium(acetylacetonate) [(fbi) 2 Ir(acac)] (orange) into the wide E g host mCP by harvesting excitons via two parallel channels with a high E T (2.7 eV) of TAZ as the ET material. With a device structure of ITO/NPB/TCTA/mCP: FIrpic:(fbi) 2 Ir(acac)/TAZ/ LiF/Al, white emission with a maximum PE of 42.5 lm/W, a peak EQE of 19.3%, and CIE coordinates (0.30-0.32, 0.37-0.38) was obtained.…”

Section: White Emission Containing Double Emittersmentioning

confidence: 99%

Recent Progresses on Materials for Electrophosphorescent Organic Light‐Emitting Devices

et al. 2010

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Although organic light-emitting devices have been commercialized as flat panel displays since 1997, only singlet excitons were emitted. Full use of singlet and triplet excitons, electrophosphorescence, has attracted increasing attentions after the premier work made by Forrest, Thompson, and co-workers. In fact, red electrophosphorescent dye has already been used in sub-display of commercial mobile phones since 2003. Highly efficient green phosphorescent dye is now undergoing of commercialization. Very recently, blue phosphorescence approaching the theoretical efficiency has also been achieved, which may overcome the final obstacle against the commercialization of full color display and white light sources from phosphorescent materials. Combining light out-coupling structures with highly efficient phosphors (shown in the table-of-contents image), white emission with an efficiency matching that of fluorescent tubes (90 lm/W) has now been realized. It is possible to tune the color to the true white region by changing to a deep blue emitter and corresponding wide gap host and transporting material for the blue phosphor. In this article, recent progresses in red, green, blue, and white electrophosphorescent materials for OLEDs are reviewed, with special emphasis on blue electrophosphorescent materials.

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Section: White Emission Containing Double Emittersmentioning

confidence: 99%

Recent Progresses on Materials for Electrophosphorescent Organic Light‐Emitting Devices

et al. 2010

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“…[ 11 ] To the best of our knowledge, device C3 would be the fi rst nondoped device based on a Pt phosphor realizing a high EQE of ∼ 10% in the visible region. [ 6b , 12 ] Several trends can be found from the performance data of these devices.…”

Section: Doped and Non-doped Electrophosphorescent Devices Based On Tmentioning

confidence: 99%

Platinum Phosphors Containing an Aryl‐modified β‐Diketonate: Unusual Effect of Molecular Packing on Photo‐ and Electroluminescence

Chen

Tsai

et al. 2011

Adv Funct Materials

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Three new FPt1 [(2‐(4′,6′‐difluorophenyl)pyridinato‐N,C2′)(2,4‐pentanedionato‐ O,O)Pt(II)] analogues, Ph‐FPt, CzP‐FPt, and mCzP‐FPt, chelated with a 3‐aryl‐substituted acac ligand were synthesized. As shown by the results of X‐ray diffraction, the nearest neighboring molecules in the FPt1, Ph‐FPt, and CzP‐FPt crystals have a Pt–Pt distance of ~4.5, 4.5, and 7.0 Å, respectively. In contrast, in the mCzP‐FPt crystals, the nearest neighboring molecules exhibit a Pt–Pt distance of only 3.49 Å. All four Pt complexes show the same monomeric emission spectrum in dilute solution. However, in the crystalline state, mCzP‐FPt with a clear Pt–Pt bimetallic interaction shows only the low‐energy orange broadband emission; complexes FPt1, Ph‐FPt, and CzP‐FPt without significant Pt–Pt interaction (Pt–Pt distance > 4 Å) give higher‐energy emission closely resembling that of the monomeric species. The results provide clear evidence that the Pt–Pt bimetallic interaction is responsible for the low‐energy broadband emission of these Pt complexes. Unlike in the crystalline state, all of the four platinum complexes in the thin film give only the low‐energy broadband emissions with some difference in wavelength. In a similar manner, these platinum complexes‐based, non‐doped electroluminescence (EL) devices also emit only low‐energy orange broadband light. The non‐doped EL device using CzP‐FPt as the emitter showed a very promising external quantum efficiency of 10%, nearly five times higher than that of the FPt1 control device. The higher EL efficiency of the CzP‐FPt non‐doped device is mainly ascribed to the lower concentration of Pt–Pt dimers that effectively suppresses the self‐quenching between the orange emissive dimers.

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“…[5][6][7] WOLEDs based on all phosphorescent emitters have been shown to achieve an internal quantum efficiency of 100% as compared with the theoretical value of 25% in that of devices based on all fluorescent emitters. [8][9][10] However, one bottleneck for further improving the performance (especially the lifetimes) of fully phosphorescent WOLEDs is the lack of stable and efficient blue phosphorescent emitters which lag far behind than green and red phosphorescent emitters. [11][12][13] Although many blue phosphorescent emitters have been reported, the lifetimes of the WOLEDs based on widely used blue phosphorescent emitters, iridium(III) bis [(4,6-…”

mentioning

confidence: 99%

Efficient fluorescence/phosphorescence white organic light-emitting diodes with ultra high color stability and mild efficiency roll-off

Tao

Huang

et al. 2015

Applied Physics Letters

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Efficient fluorescence/phosphorescence hybrid white organic light-emitting diodes (OLEDs) with single doped co-host structure have been fabricated. Device using 9-Naphthyl-10 -(4-triphenylamine)anthrancene as the fluorescent dopant and Ir(ppy)3 and Ir(2-phq)3 as the green and orange phosphorescent dopants show the luminous efficiency of 12.4% (17.6 lm/W, 27.5 cd/A) at 1000 cd/m2. Most important to note that the efficiency-brightness roll-off of the device was very mild. With the brightness rising up to 5000 and 10 000 cd/m2, the efficiency could be kept at 11.8% (14.0 lm/W, 26.5 cd/A) and 11.0% (11.8 lm/W, 25.0 cd/A). The Commission Internationale de L'Eclairage (CIE) coordinates and color rending index (CRI) were measured to be (0.45, 0.48) and 65, respectively, and remained the same in a large range of brightness (1000–10 000 cd/m2), which is scarce in the reported white OLEDs. The performance of the device at high luminance (5000 and 10 000 cd/m2) was among the best reported results including fluorescence/phosphorescence hybrid and all-phosphorescent white OLEDs. Moreover, the CRI of the white OLED can be improved to 83 by using a yellow-green emitter (Ir(ppy)2bop) in the device.

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Harvesting Excitons Via Two Parallel Channels for Efficient White Organic LEDs with Nearly 100% Internal Quantum Efficiency: Fabrication and Emission‐Mechanism Analysis

Cited by 394 publications

References 84 publications

Recent Progresses on Materials for Electrophosphorescent Organic Light‐Emitting Devices

Recent Progresses on Materials for Electrophosphorescent Organic Light‐Emitting Devices

Platinum Phosphors Containing an Aryl‐modified β‐Diketonate: Unusual Effect of Molecular Packing on Photo‐ and Electroluminescence

Efficient fluorescence/phosphorescence white organic light-emitting diodes with ultra high color stability and mild efficiency roll-off

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