scholarly journals Hot exciplexes in U-shaped TADF molecules with emission from locally excited states

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
A. Lennart Schleper ◽  
Kenichi Goushi ◽  
Christoph Bannwarth ◽  
Bastian Haehnle ◽  
Philipp J. Welscher ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Donor And Acceptor ◽  
Low Efficiency ◽  
High Color Purity

AbstractFast emission and high color purity are essential characteristics of modern opto-electronic devices, such as organic light emitting diodes (OLEDs). These properties are currently not met by the latest generation of thermally activated delayed fluorescence (TADF) emitters. Here, we present an approach, called “hot exciplexes” that enables access to both attributes at the same time. Hot exciplexes are produced by coupling facing donor and acceptor moieties to an anthracene bridge, yielding an exciplex with large T1 to T2 spacing. The hot exciplex model is investigated using optical spectroscopy and quantum chemical simulations. Reverse intersystem crossing is found to occur preferentially from the T3 to the S1 state within only a few nanoseconds. Application and practicality of the model are shown by fabrication of organic light-emitting diodes with up to 32 % hot exciplex contribution and low efficiency roll-off.

Solution-processable orange-red thermally activated delayed fluorescence emitters with 3,6-disubstituted carbazole for highly efficient OLEDs with low efficiency roll-off

2022 ◽  
Author(s):  
Yaxing Zhang ◽  
Yuanyuan Zheng ◽  
Changsheng Shi ◽  
Jinyan Zhang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Green Materials ◽  
Device Efficiency ◽  
Low Efficiency

The progress of orange-red thermally activated delayed fluorescence (TADF) emitters for solution-processed organic light-emitting diodes (OLEDs) is still lagged behind blue and green materials in terms of device efficiency. In...

scholarly journals Hot Exciplexes in U-Shaped TADF Molecules with Emission from Locally Excited States

2021 ◽  
Author(s):  
A. Lennart Schleper ◽  
Kenichi Goushi ◽  
Christoph Bannwarth ◽  
Bastian Haehnle ◽  
Philipp Welscher ◽  
...  
Keyword(s):  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Intersystem Crossing ◽  
Thermally Activated Delayed Fluorescence ◽  
New Approach ◽  
Light Emitting ◽  
Thermally Activated ◽  
Donor And Acceptor ◽  
Low Efficiency ◽  
High Color Purity

Rapid reverse intersystem crossing and high color purity are vital characteristics of emitters with thermally activated delayed fluorescence in opto-electronic devices. We present a new approach, called “hot exciplexes” that enables access to both attributes at the same time. Hot exciplexes are produced by coupling facing donor and acceptor moieties to an anthracene bridge, yielding an exciplex with large T1 to T2 spacing. The hot exciplex model is investigated using optical spec-troscopy and quantum chemical simulations. Reverse intersystem crossing is found to occur preferentially from the T3 to the S1 state within only a few nanoseconds. Application and practi-cality of the model are shown by fabrication of organic light-emitting diodes with up to 32 % hot exciplex contribution and low efficiency roll-off.

scholarly journals Triazine-Acceptor-Based Green Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2646 ◽  
Author(s):  
Ramanaskanda Braveenth ◽  
Kyu Yun Chai
Keyword(s):  
Light Emitting Diodes ◽  
Molecular Design ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Potential Candidate ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Donor And Acceptor

High-efficiency thermally activated delayed fluorescence (TADF) is leading the third-generation technology of organic light-emitting diodes (OLEDs). TADF emitters are designed and synthesized using inexpensive organic donor and acceptor derivatives. TADF emitters are a potential candidate for next-generation display technology when compared with metal-complex-based phosphorescent dopants. Many studies are being conducted to enhance the external quantum efficiencies (EQEs) and photoluminescent quantum yield of green TADF devices. Blue TADF reached an EQE of over 35% with the support of suitable donor and acceptor moieties based on a suitable molecular design. The efficiencies of green TADF emitters can be improved when an appropriate molecular design is applied with an efficient device structure. The triazine acceptor has been identified as a worthy building block for green TADF emitters. Hence, we present here a review of triazine with various donor molecules and their device performances. This will help to design more suitable and efficient green TADF emitters for OLEDs.

Naphthyridine-based thermally activated delayed fluorescence emitters for multi-color organic light-emitting diodes with low efficiency roll-off

2019 ◽  
Vol 7 (16) ◽  
pp. 4673-4680 ◽  
Author(s):  
Cheng Chen ◽  
Hai-Yan Lu ◽  
Yin-Feng Wang ◽  
Meng Li ◽  
Yi-Fan Shen ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Low Efficiency

1,8-Naphthyridine-based TADF molecules were utilized as a new kind of emitter for multi-color OLEDs with low efficiency roll-off.

scholarly journals Stable green phosphorescence organic light-emitting diodes with low efficiency roll-off using a novel bipolar thermally activated delayed fluorescence material as host

2017 ◽  
Vol 8 (2) ◽  
pp. 1259-1268 ◽  
Author(s):  
Kunping Guo ◽  
Hedan Wang ◽  
Zixing Wang ◽  
Changfeng Si ◽  
Cuiyun Peng ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Low Efficiency ◽  
Fluorescence Material

A bipolar host with TADF properties is realized, endowing green PhOLEDs with a twentyfold lifetime improvement.

Highly efficient thermally activated delayed fluorescence yellow organic light-emitting diodes with a low efficiency roll-off

2019 ◽  
Vol 7 (26) ◽  
pp. 8063-8069 ◽  
Author(s):  
Xiang-Long Li ◽  
Xinyi Cai ◽  
Muhammad Umair Ali ◽  
Shi-Jian Su ◽  
Hong Meng
Keyword(s):  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Highly Efficient ◽  
Organic Light ◽  
Device Engineering ◽  
Low Efficiency

Highly efficient TADF yellow OLEDs with an extremely low efficiency roll-off have been obtained herein via rational device engineering.

scholarly journals Hot Exciplexes in U-Shaped TADF Molecules with Emission from Locally Excited States

2021 ◽  
Author(s):  
A. Lennart Schleper ◽  
Kenichi Goushi ◽  
Christoph Bannwarth ◽  
Bastian Haehnle ◽  
Philipp Welscher ◽  
...  
Keyword(s):  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Intersystem Crossing ◽  
Thermally Activated Delayed Fluorescence ◽  
New Approach ◽  
Light Emitting ◽  
Thermally Activated ◽  
Donor And Acceptor ◽  
Low Efficiency ◽  
High Color Purity

Rapid reverse intersystem crossing and high color purity are vital characteristics of emitters with thermally activated delayed fluorescence in opto-electronic devices. We present a new approach, called “hot exciplexes” that enables access to both attributes at the same time. Hot exciplexes are produced by coupling facing donor and acceptor moieties to an anthracene bridge, yielding an exciplex with large T1 to T2 spacing. The hot exciplex model is investigated using optical spec-troscopy and quantum chemical simulations. Reverse intersystem crossing is found to occur preferentially from the T3 to the S1 state within only a few nanoseconds. Application and practi-cality of the model are shown by fabrication of organic light-emitting diodes with up to 32 % hot exciplex contribution and low efficiency roll-off.

scholarly journals Solution-Processed Pure Blue Thermally Activated Delayed Fluorescence Emitter Organic Light-Emitting Diodes With Narrowband Emission

2021 ◽  
Vol 9 ◽  
Author(s):  
Ting Xu ◽  
Xiao Liang ◽  
Guohua Xie
Keyword(s):  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Color Purity ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
High Color Purity

There is a need to satisfy the high color purity requirement of display technology with a simply fabricated process. Herein, solution-processed blue thermally activated delayed fluorescence organic light-emitting diodes (OLEDs) with a narrow spectrum with a full width at half maximum (FWHM) of 32 nm and y color coordinate below 0.2 are demonstrated by employing a molecule containing boron and nitrogen atoms (TBN-TPA) as the guest emitter in the emissive layer. The opposite resonance positions of B-N atoms of TBN-TPA endows a multi-resonance effect, leading to high color purity.

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