Operational lifetime improvement of solution-processed OLEDs: Effect of exciton formation region and degradation analysis by impedance spectroscopy

Le, Thi Na; Park, Eun Young; Vasudevan, Thangaraji; Suh, Min Chul

doi:10.1016/j.orgel.2021.106346

Cited by 16 publications

(28 citation statements)

References 39 publications

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“…This large difference in mobility of x-HTL and s-ETL can cause the exciton formation region to occur at the mixing interface between x-HTL and EML, resulting in low performance and short lifetime. [3] Furthermore, we also calculated the mobility of LG201:Liq layer with ratios of (1:1), (1:1.7), and (1:0.3).…”

Section: Resultsmentioning

confidence: 99%

“…Cross-linkable hole transport material (x-HTM) and materials for emitting layer (EML) were reported elsewhere. [3] 2,4-diphenyl-6-bis(12-phenylindolo)[2,3-a] carbazole-11-yl)-1,3,5-triazine (DIC-TRZ), purchased from Lumtec, was used as exciton blocking layer (EBL). Lithium quinolate (Liq, Sigma Aldrich) was used in ETL and also as electron injection layer.…”

Section: Methodsmentioning

confidence: 99%

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52.4: Suppression of Initial Degradation for High‐Efficiency Solution‐Processed Organic Light Emitting Diodes

Lee

Park

et al. 2022

Symp Digest of Tech Papers

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In OLED display, the burn‐in usually appears when the luminance is reduced by 3% or 5 % (LT97 or LT95). This means that extending the LT95 or LT97 is essential to bring OLED display one step closer to becoming a dominant display technic. Here, we report an improvement in initial stability by designing a double electron transport layer which results in overshooting effect. This effect can suppressed the initial degradation in the device. We successfully increased the LT95 by 7.3 times and LT97 by 8.8 times. Simultaneously, the trade‐off between lifetime and efficiency was eliminated as we also obtained very high efficiency of 91.8 cd/A and 26.5% EQE.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

52.4: Suppression of Initial Degradation for High‐Efficiency Solution‐Processed Organic Light Emitting Diodes

Lee

Park

et al. 2022

Symp Digest of Tech Papers

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“…Recently, much effort has been devoted to highlighting the advantages of solution-processed OLED devices. [1,2] However, the solution-processed OLED still have lower efficiency compared to vacuum deposition ones. The reason is not only originated from the interface mixing between hole transport layer (HTL) and emitting layer (EML), but also lack of research on materials for the solution process.…”

Section: Objective and Backgroundmentioning

confidence: 99%

“…Nevertheless, the host material PCIC in the above device is also hole-transport type host material having low electron mobility [2] . And, the LUMO energy barrier between PCIC and TPBi is quite large lowering the electron injection efficiency.…”

Section: Performances Of Solution-processed Greenmentioning

confidence: 99%

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P‐135: New Hole‐Transport Materials Composed of Indenocarbazole‐Based Copolymer for Ultra‐High‐Efficiency Solution‐Processed OLED

Kim

Lee

et al. 2022

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New hole transport indenocarbazole based copolymers, KHU‐HTL1 and KHU‐HTL2, were found to have good solubility, intermediate HOMO levels, especially good charge transport properties due to low hole reorganization energy. Subsequently, the device with KHU‐HTL1 showed a maximum current efficiency up to 100.4 cd/A. To the best of our knowledge, the efficiency value we achieved from the solution processed green phosphorescent OLEDs with this material is one of the best efficiency realized from solution‐processed OLED.

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Management of Host–Guest Triplet Exciton Distribution for Stable, High‐Efficiency, Low Roll‐Off Solution‐Processed Blue Organic Light‐Emitting Diodes by Employing Triplet‐Energy‐Mediated Hosts

Liu

Qiu

et al. 2023

Adv Funct Materials

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High‐quality hosts are indispensable for simultaneously realizing stable, high efficiency, and low roll‐off blue solution‐processed organic light‐emitting diodes (OLEDs). Herein, three solution processable bipolar hosts with successively reduced triplet energies approaching the T1 state of thermally activated delayed fluorescence (TADF) emitter are developed and evaluated for high‐performance blue OLED devices. The smaller T1 energy gap between host and guest allows the quenching of long‐lived triplet excitons to reduce exciton concentration inside the device, and thus suppresses singlet‐triplet and triplet‐triplet annihilations. Triplet‐energy‐mediated hosts with high enough T1 and better charge balance in device facilitate high exciton utilization efficiency and uniform triplet exciton distribution among host and TADF guest. Benefited from these synergetic factors, a high maximum external quantum efficiency (EQEmax) of 20.8%, long operational lifetime (T50 of 398.3 h @ 500 cd m−2), and negligible efficiency roll‐off (EQE of 20.1% @ 1000 cd m−2) are achieved for bluish‐green TADF OLEDs. Additionally introducing a narrowband emission multiple‐resonance TADF material as terminal emitter to accelerate exciton dynamic and improve exciton utilization, a higher EQEmax of 23.1%, suppressed roll‐off and extended lifetime of 456.3 h are achieved for the sky‐blue sensitized OLEDs at the same brightness.

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Operational lifetime improvement of solution-processed OLEDs: Effect of exciton formation region and degradation analysis by impedance spectroscopy

Cited by 16 publications

References 39 publications

52.4: Suppression of Initial Degradation for High‐Efficiency Solution‐Processed Organic Light Emitting Diodes

52.4: Suppression of Initial Degradation for High‐Efficiency Solution‐Processed Organic Light Emitting Diodes

P‐135: New Hole‐Transport Materials Composed of Indenocarbazole‐Based Copolymer for Ultra‐High‐Efficiency Solution‐Processed OLED

Management of Host–Guest Triplet Exciton Distribution for Stable, High‐Efficiency, Low Roll‐Off Solution‐Processed Blue Organic Light‐Emitting Diodes by Employing Triplet‐Energy‐Mediated Hosts

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