White organic light-emitting devices with a phosphorescent multiple emissive layer

Cheng, Gang; Zhang, Yingfang; Zhao, Yi; Lin, Yuanyuan; Ruan, Chunyan; Liu, Shiyong; Teng, Fei; Ma, Yan; Cheng, Yanxiang

doi:10.1063/1.2227645

Cited by 68 publications

(32 citation statements)

References 28 publications

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“…[ 213 , 214 ] To harvest all triplet excitons, devices containing triple phosphors with separated or mixed emission layers were designed. [215][216][217][218] Sun and Forrest [ 215 , 216 ] combined red phosphorescent emitter of Ir (III) bis-(2-phenylquinolyl-N , C 2 ′ ) acetylacetonate (PQIr)-doped TCTA, and green phosphorescent emitter of Ir(ppy) 3 -doped mCP, with blue phosphorescent emitter of FIr6-doped in wide E g host of UGH2 and improved the peak forward-viewing EQE up to 16.6%, PE up to 32 lm/W with a CRI of 81 and CIE coordinates of (0.35-0.37, 0.38-0.41). The EQE was higher than those of the corresponding monochrome devices, suggesting that excitons were formed in multiple zones within the device.…”

Section: White Emission Containing Triple 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 Triple Emittersmentioning

confidence: 99%

Recent Progresses on Materials for Electrophosphorescent Organic Light‐Emitting Devices

et al. 2010

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“…[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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“…Therefore, the blue EML in phosphorescent M-EML WOLEDs should be thicker than the other EMLs to balance the emission of each color. [227][228][229][230] Energy transfer in S-EML WOLEDs takes place even more actively between dopants as well as between the host and the dopants for both fluorescent as well as phosphorescent dyes because all materials are blended together, and the distance between dopants is comparably short. This fact indicates that the green and red emission intensities will be stronger than the blue emission, if the concentration of green and red dopants is similar to that of the blue dopant.…”

Section: Energy Transfer In Phosphorescent Oledsmentioning

confidence: 99%

“…Very high efficiencies were obtained from the phosphorescent polymer. [215] Energy Transfer in White OLEDs [216][217][218][219][220][221][222][223][224][225][226] or multi-emitting layer (M-EML) devices doped with single dyes in each layer [227][228][229][230][231][232][233][234][235][236][237][238][239][240][241][242][243][244] have been utilized. Both fluorescent as well as phosphorescent dyes can be used as the emitting materials.…”

Section: Energy Transfer In Phosphorescent Oledsmentioning

confidence: 99%

Excitation Energy Transfer in Organic Materials: From Fundamentals to Optoelectronic Devices

Laquai

Park

Kim

et al. 2009

Macromol. Rapid Commun.

184

146

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In this review, we discuss investigations of electronic excitation energy transfer in conjugated organic materials at the bulk and single molecule level and applications of energy transfer in fluorescent and phosphorescent organic light emitting devices. A brief overview of common descriptions of energy transfer mechanisms is given followed by a discussion of some basic photophysics of conjugated materials including the generation of excited states and their subsequent decay through various channels. In particular, various examples of bimolecular excited state annihilation processes are presented. Energy transfer studies at the single molecule level provide a new tool to study electronic couplings in simple donor/acceptor dyads and conjugated polymers. Finally, energy transfer in organic electronic devices is discussed with particular emphasis on triplet emitter doped OLEDs and blends for white light emission.

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White organic light-emitting devices with a phosphorescent multiple emissive layer

Cited by 68 publications

References 28 publications

Recent Progresses on Materials for Electrophosphorescent Organic Light‐Emitting Devices

Recent Progresses on Materials for Electrophosphorescent Organic Light‐Emitting Devices

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

Excitation Energy Transfer in Organic Materials: From Fundamentals to Optoelectronic Devices

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