Improvement of efficiency roll-off in blue phosphorescence OLED using double dopants emissive layer

Yoo, Seung Il; Yoon, Ju An; Kim, Nam Ho; Kim, Jin Wook; Kang, Jin Sung; Moon, Chang-Bum; Kim, Woo Young

doi:10.1016/j.jlumin.2014.12.028

Cited by 18 publications

(6 citation statements)

References 21 publications

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“…Furthermore, FIrpic provides an additional channel to facilitate charge transport for the EML, [12] which can also be inferred from its lowest unoccupied molecular orbital (LUMO) level. [13] On the other hand, the high triplet energy of FIrpic (2.75 eV) [14] prevents exchange energy from being lost from host-guest EML to ETL and suppresses the energy transport from EML to ETL. To summarize, the FIrpic enhances the efficiency and luminance of the device.…”

Section: Resultsmentioning

confidence: 99%

High-efficiency organic light-emitting diodes based on ultrathin blue phosphorescent modification layer

Zhu¹,

Zhong²,

Lei³

et al. 2017

Chinese Phys. B

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Yellow organic light-emitting devices (YOLEDs) with a novel structure of ITO/MoO 3 (5 nm)/NPB(40 nm)/ TCTA(15 nm)/CBP:(tbt) 2 Ir(acac)(x%)(25 nm)/FIrpic(y nm)/TPBi(35 nm)/Mg:Ag are fabricated. The ultrathin blue phosphorescent bis [(4,6-difluorophenyl)-pyridi-nato-N,C2 ](picolinate) iridium (III) (FIrpic) layer is regarded as a highperformance modification layer. By adjusting the thickness of FIrpic and the concentration of (tbt) 2 Ir(acac), a YOLED achieves a high luminance of 41618 cd/m 2 , power efficiency of 49.7 lm/W, current efficiency of 67.3 cd/A, external quantum efficiency (EQE) of 18%, and a low efficiency roll-off at high luminance. The results show that phosphorescent material of FIrpic plays a significant role in improving YOLED performance. The ultrathin FIrpic modification layer blocks excitons in EML. In the meantime, the high triplet energy of FIrpic (2.75 eV) alleviates the exciton energy transport from EML to FIrpic.

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Section: Resultsmentioning

confidence: 99%

High-efficiency organic light-emitting diodes based on ultrathin blue phosphorescent modification layer

Zhu¹,

Zhong²,

Lei³

et al. 2017

Chinese Phys. B

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“…Afterwards in 2021, Braveenth et al 90 Current efficiency.-The ratio of luminescence over current density is defined as current efficiency. [100][101][102] This parameter has been investigated widely to refine the performance of OLED devices. A heterojunction organic bipolar charge injection layer with zinc phthalocyanine: fullerene (ZnPc:C 60 ) is reported by Chen et al 8 The maximum current efficiency is obtained as 36.5 cdA −1 .…”

Section: Characteristics Parameters For Oledmentioning

confidence: 99%

Review—Advancements and Perspectives of Organic LED: In Depth Analysis of Architectural Design, Characteristics Parameters, Fabrication Techniques, and Applications

Yadav

Mittal

Negi

2023

ECS J. Solid State Sci. Technol.

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This article presents a review on various aspect of organic light emitting diodes (OLEDs), such as their working, various categorization, impact of fabrication methodologies (organic vapor phase deposition, vacuum thermal evaporation, inkjet printing etc.) that are low-cost and their applications in serval domains like medical, sensor, display, lighting etc. Three categorizations of OLED are discussed with respect to circuit, architecture and color of emission. Different layers of multi-layered structures such as injection layer, transport layer, block layers are also reviewed and their impacts are analyzed and compared. Moreover, an experimental fabrication technique for flexible substrate is reviewed that highlights low-cost fabrication method. In this technique, dynamic viscosity and contact angle are measured using rotational viscometer and contact angle meter, respectively. The result illustrates sheet resistance and effective opening ratio of 3.8 ohms per square and 82.5%, correspondingly. Additionally, various performance parameters like luminescence, external quantum efficiency, and current efficiency are compared. The paper also incorporates recent advancement in organic thin film transistors along with some OTFT driven OLED devices.

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“…Baldo and co-workers used green phosphor fac-Tris(2-phenylpyridine)iridium(III) (Ir(ppy) 3 ) as a sensitizer to facilitate the transfer of triplet energy to red fluorescent emitter 4-(Dicyanomethylene)-2-methyl-6-julolidyl-9-enyl-4H-pyran (DCM2) and realized significantly higher DCM2 emission efficiency [ 33 ]. Seung et al selected double dopants of FIrpic and FIr6 to obtain the device with maximum CE of 24.8 cd/A and slow efficiency roll-off, and they proved the efficacy of the second dopant in stabilizing carriers’ balance within the light-emitting layer (EML) and enhancing the energy transfer between two dopants [ 34 ].…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Solution-Processed Blue Phosphorescent Organic Light-Emitting Diodes Based on Co-Dopant and Co-Host System

Wang

Yin²,

Li³

et al. 2022

Molecules

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The low-lying HOMO level of the blue emitter and the interfacial miscibility of organic materials result in inferior hole injection, and long exciton lifetime leads to triplet-triplet annihilation (TTA) and triplet-polaron annihilation (TPA), so the efficiencies of blue phosphorescent organic light-emitting diodes (PhOLEDs) are still unsatisfactory. Herein, we design co-host and co-dopant structures to improve the efficiency of blue PhOLEDs by means of solution processing. TcTa acts as hole transport ladder due to its high-lying HOMO level, and bipolar mCPPO1 helps to balance carriers’ distribution and weaken TPA. Besides the efficient FIr6, which acts as the dominant blue dopant, FCNIrPic was introduced as the second dopant, whose higher HOMO level accelerates hole injection and high triplet energy facilitates energy transfer. An interesting phenomenon caused by microcavity effect between anode and cathode was observed. With increasing thickness of ETL, peak position of electroluminescence (EL) spectrum red shifts gradually. Once the thickness of ETL exceeded 140 nm, emission peak blue-shifts went back to its original position. Finally, the maximum current efficiency (CE), power efficiency (PE), and external quantum efficiency (EQE) of blue phosphorescent organic light-emitting diode (PhOLED) went up to 20.47 cd/A, 11.96 lm/W, and 11.62%, respectively.

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Improvement of efficiency roll-off in blue phosphorescence OLED using double dopants emissive layer

Cited by 18 publications

References 21 publications

High-efficiency organic light-emitting diodes based on ultrathin blue phosphorescent modification layer

High-efficiency organic light-emitting diodes based on ultrathin blue phosphorescent modification layer

Review—Advancements and Perspectives of Organic LED: In Depth Analysis of Architectural Design, Characteristics Parameters, Fabrication Techniques, and Applications

Highly Efficient Solution-Processed Blue Phosphorescent Organic Light-Emitting Diodes Based on Co-Dopant and Co-Host System

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