scholarly journals Effect of TADF Assistance on Performance Enhancement in Solution Processed Green Phosphorescent OLEDs

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1148
Author(s):  
Ewelina Witkowska ◽  
Gabriela Wiosna-Salyga ◽  
Ireneusz Glowacki ◽  
Tung-Huei Ke ◽  
Pawel Malinowski ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Performance Enhancement ◽  
Charge Trapping ◽  
Delayed Fluorescence ◽  
Triplet States ◽  
Efficient Energy Transfer ◽  
Solution Processed ◽  
Light Emitting ◽  
Emissive Layer ◽  
Organic Electroluminescent

Many methods have been proposed to increase the efficiency of organic electroluminescent materials applied as an emissive layer in organic light emitting diodes (OLEDs). Herein, we demonstrate enhancement of electroluminescence efficiency and operational stability solution processed OLEDs by employing thermally activated delayed fluorescence (TADF) molecules as assistant dopants in host-guest systems. The TADF assistant dopant (SpiroAC–TRZ) is used to facilitate efficient energy transfer from host material poly(N–vinylcarbazole) (PVK) to a phosphorescent Ir(III) emitter. We present the analysis of energy transfer and charge trapping—two main processes playing a crucial role in light generation in host–guest structure OLEDs. The investigation of photo-, electro- and thermoluminescence for the double-dopant layer revealed that assistant dopant does not only harvest and transfer the electrically generated excitons to phosphorescent emitter molecules but also creates exciplexes. The triplet states of formed PVK:SpiroAC–TRZ exciplexes are involved in the transport process of charge carriers and promote long–range exciton energy transfer to the emitter, improving the efficiency of electroluminescence in a single emissive layer OLED, resulting in devices with luminance exceeding 18 000 cd/m2 with a luminous efficiency of 23 cd/A and external quantum efficiency (EQE) of 7.4%.

scholarly journals Molecular design of efficient yellow- to red-emissive alkynylgold(iii) complexes for the realization of thermally activated delayed fluorescence (TADF) and their applications in solution-processed organic light-emitting devices

2021 ◽  
Author(s):  
Cathay Chai Au-Yeung ◽  
Lok-Kwan Li ◽  
Man-Chung Tang ◽  
Shiu-Lun Lai ◽  
Wai-Lung Cheung ◽  
...  
Keyword(s):  
Molecular Design ◽  
Delayed Fluorescence ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Thermally Activated ◽  
New Class ◽  
Organic Light ◽  
Tunable Emission

We report the design of a new class of fused heterocyclic alkynyl ligand-containing gold(iii) complexes, which shows tunable emission colors spanning yellow to red region and exhibits thermally activated delayed fluorescence (TADF) properties.

scholarly journals Solution-Processed OLEDs Based on Thermally Activated Delayed Fluorescence Copper(I) Complexes with Intraligand Charge-Transfer Excited State

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1125
Author(s):  
Teng Teng ◽  
Jinfan Xiong ◽  
Gang Cheng ◽  
Changjiang Zhou ◽  
Xialei Lv ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Functional Theory ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Wide Range

A new series of tetrahedral heteroleptic copper(I) complexes exhibiting efficient thermally-activated delayed fluorescence (TADF) in green to orange electromagnetic spectral regions has been developed by using D-A type N^N ligand and P^P ligands. Their structures, electrochemical, photophysical, and electroluminescence properties have been characterized. The complexes exhibit high photoluminescence quantum yields (PLQYs) of up to 0.71 at room temperature in doped film and the lifetimes are in a wide range of 4.3–24.1 μs. Density functional theory (DFT) calculations on the complexes reveal the lowest-lying intraligand charge-transfer excited states that are localized on the N^N ligands. Solution-processed organic light emitting diodes (OLEDs) based on one of the new emitters show a maximum external quantum efficiency (EQE) of 7.96%.

Efficient triplet utilization in conventional solution-processed phosphorescent organic light emitting diodes using a thermal activated delayed fluorescence polymer as an assistant host

2018 ◽  
Vol 6 (17) ◽  
pp. 4800-4806 ◽  
Author(s):  
Dianming Sun ◽  
Zhongjie Ren ◽  
Shouke Yan
Keyword(s):  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Host Material ◽  
Solution Processed ◽  
Light Emitting ◽  
Organic Light ◽  
Conventional Solution

A TADF polymer COPO is used as an assistant host material to improve the performance of Ir(mPPy)3-based solution-processed devices.

Asymmetric Sky-Blue Thermally Activated Delayed Fluorescence Emitters Bearing Tris(triazolo)triazine Moiety for Solution Processable Organic Light-Emitting Diodes

2022 ◽  
Author(s):  
Zhou Fang ◽  
Shengyue Wang ◽  
Junxu Liao ◽  
Xinrui Chen ◽  
Yuanyuan Zhu ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Solution Processable

Efficient blue thermally activated delayed fluorescence (TADF) emitter is still a challenge in solution-processed organic light-emitting diodes (OLEDs). In this contribution, two asymmetric molecules of TTT-Ac and TTT-2Ac were synthesized...

Exciton energy transfer and bi-exciton annihilation in the emitting layers of thermally activated delayed fluorescence-based OLEDs

2021 ◽  
Author(s):  
Hyunchul Kang ◽  
Han-Jin Ahn ◽  
Gyeong-Woo Kim ◽  
Ji-Eun Jeong ◽  
Han Young Woo ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Exciton Energy ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Exciton Annihilation

Understanding the exciton energy transfer and bi-exciton annihilation processes in the emitting layers (EMLs) of thermally activated delayed fluorescence (TADF)-based organic light-emitting diodes (OLEDs) is essential for improving their internal...

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