Doping-free tandem white organic light-emitting diodes

Liu, Baiquan; Wang, Lei; Xu, Miao; Zou, Jianhua; Ning, Honglong; Peng, Junbiao; Cao, Yong

doi:10.1016/j.scib.2017.08.021

Cited by 40 publications

(31 citation statements)

References 54 publications

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“…For example, at a practical luminance of 3000 cd/m 2 , the CE and EQE are still up to 61.40 cd/A and 28.13% for device W4, 58.10 cd/A and 27.04% for device W5, and 49.06 cd/A and 24.73% for device W6, respectively. The optimized tandem white device W4 simultaneously achieves superior device efficiency (76.16 cd/A)/CRI (91)/ color stability, which, is the first tandem white OLED with only two EL units realizing such high device performance, to the best of our knowledge [29,34,35,[40][41][42][43][44][45][46][47][48] and the detailed comparisons are shown in Table S1 in Supporting information. The achievement for such high device performance is attributed to i) an excellent charge generation ability for the optimized CGU; ii) the good management of carrier recombination zone and precise manipulation and efficient utilization of generated excitons by symmetrical EMLs [38].…”

Section: Tandem Woleds Stacked With Two Symmetrical El Unitsmentioning

confidence: 99%

Tandem white organic light-emitting diodes stacked with two symmetrical emitting units simultaneously achieving superior efficiency/CRI/color stability

et al. 2019

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In this work, a series of three and four-color tandem white organic light-emitting diodes (WOLEDs) are developed by using the optimized charge generating unit (CGU) to connect two electroluminescence (EL) units with symmetrical emitting layers, in which symmetrical emitting layers are constructed based on the mixed hosts; sandwiched between hole and electron-transporting hosts and the light emitted from two EL units that are absolutely complementary for forming white emission. All resulting tandem WOLEDs realize good white emission with maximum color rendering index (CRI) beyond 77 and 90 for three and four-color white devices and extremely high EL spectra stability, and also achieve high device efficiency with maximum external quantum efficiency (EQE) exceeding 33.10%. For example, for the optimized four-color tandem WOLED, the maximum CRI and EQE of 91 and 34.78% are demonstrated and only very slight CIE (Δx, Δy) variation of (0.002, −0.010) was observed at a wide luminance range from 170.9 cd/m2 to 13,870 cd/m2. To the best of our knowledge, this is the first tandem WOLED with only two EL units realizing such high device performances. More importantly, the proposed tandem WOLEDs here avoid introducing carrier or exciton blocking layer or using more EL units to realize high color quality white emission that provides a novel approach to develop simple, but high-performance tandem WOLEDs.

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Section: Tandem Woleds Stacked With Two Symmetrical El Unitsmentioning

confidence: 99%

Tandem white organic light-emitting diodes stacked with two symmetrical emitting units simultaneously achieving superior efficiency/CRI/color stability

et al. 2019

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“…In the case of the cost issue, TADF emitters are promising to lower the cost, since they naturally possess the noble metal-free characteristics. Besides, simple fabrication techniques (e.g., solution-processed technology [200][201][202][203]) and simplified device structures (e.g., doping-free architectures [204][205][206][207]) are conducive. By virtue of these technologies, the cost of WOLEDs based on TADF can be further reduced.…”

Section: Discussionmentioning

confidence: 99%

Emergence of White Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence

Xiao

Dong²,

Xie

et al. 2018

Applied Sciences

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Recently, thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have attracted both academic and industrial interest due to their extraordinary characteristics, such as high efficiency, low driving voltage, bright luminance, lower power consumption and potentially long lifetime. In this invited review, the fundamental concepts of TADF have been firstly introduced. Then, main approaches to realize WOLEDs based on TADF have been summarized. More specifically, the recent development of WOLEDs based on all TADF emitters, WOLEDs based on TADF and conventional fluorescence emitters, hybrid WOLEDs based on blue TADF and phosphorescence emitters and WOLEDs based on TADF exciplex host and phosphorescence dopants is highlighted. In particular, design strategies, device structures, working mechanisms and electroluminescent processes of the representative WOLEDs based on TADF are reviewed. Finally, challenges and opportunities for further enhancement of the performance of WOLEDs based on TADF are presented.

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“…Remarkably, the WOLED can exhibit a good color-stability, which is attributed to the avoidance of the movement of the charge recombination zone and elimination of the energy transfer between blue and yellow EMLs. Currently, the utilization of tandem OLEDs, which refer to devices using charge generation layers (CGLs) or transparent conductive layers (e.g., ITO) to interconnect multiple EL units, has been considered to be an effective way to boost the performance [160][161][162][163]. Compared with single-unit OLEDs, the CE, EQE and lifetime of tandem OLEDs can be N-fold (N, the number of EL units) enhanced, since N-fold luminance can be achieved with the current density similar to that of single-unit OLEDs.…”

Section: Woleds Utilizing All Exciplex Emittersmentioning

confidence: 99%

Recent Advances of Exciplex-Based White Organic Light-Emitting Diodes

Xiao

Huang

et al. 2018

Applied Sciences

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Recently, exciplexes have been actively investigated in white organic light-emitting diodes (WOLEDs), since they can be effectively functioned as (i) fluorescent or thermally activated delayed fluorescent (TADF) emitters; (ii) the hosts of fluorescent, phosphorescent and TADF dopants. By virtue of the unique advantages of exciplexes, high-performance exciplex-based WOLEDs can be achieved. In this invited review, we have firstly described fundamental concepts of exciplexes and their use in organic light-emitting diodes (OLEDs). Then, we have concluded the primary strategies to develop exciplex-based WOLEDs. Specifically, we have emphasized the representative WOLEDs using exciplex emitters or hosts. In the end, we have given an outlook for the future development of exciplex-based WOLEDs.

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Doping-free tandem white organic light-emitting diodes

Cited by 40 publications

References 54 publications

Tandem white organic light-emitting diodes stacked with two symmetrical emitting units simultaneously achieving superior efficiency/CRI/color stability

Tandem white organic light-emitting diodes stacked with two symmetrical emitting units simultaneously achieving superior efficiency/CRI/color stability

Emergence of White Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence

Recent Advances of Exciplex-Based White Organic Light-Emitting Diodes

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