Triplet Harvesting in White Organic Light-Emitting Diodes

2014 ◽  
Vol 1629 ◽  
Author(s):  
Simone Hofmann ◽  
Karl Leo ◽  
Malte C. Gather
Keyword(s):  
Recent Work ◽  
Single Unit ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Triplet Energy ◽  
Light Emitting ◽  
Organic Light ◽  
White Oleds ◽  
New Compounds ◽  
Triplet Harvesting

ABSTRACTIn this paper, we review our recent work on triplet harvesting (TH) and its application in white organic light-emitting diodes (OLEDs). This includes the configuration of highly efficient single unit two-color and tandem four-color white OLEDs reaching efficacies of more than 30 lm/W at 1000 cd/m², as well as the development of new blue fluorescent emitters. The new compounds are chemically designed to exhibit a high triplet energy to allow TH by a green phosphorescent emitter. In a first step towards white TH OLEDs, we fabricated blue-green TH OLEDs to prove the validity of our concept.

Efficient triplet harvesting in fluorescence–TADF hybrid warm-white organic light-emitting diodes with a fully non-doped device configuration

2018 ◽  
Vol 6 (15) ◽  
pp. 4257-4264 ◽  
Author(s):  
Juan Zhao ◽  
Zhan Yang ◽  
Xiaojie Chen ◽  
Zongliang Xie ◽  
Tiantian Liu ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light ◽  
White Oleds ◽  
Triplet Harvesting

An efficient triplet harvesting strategy provided for fluorescence–TADF hybrid white OLEDs with a fully non-doped device configuration.

scholarly journals High efficiency blue organic light-emitting diodes with below-bandgap electroluminescence

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria Vasilopoulou ◽  
Abd. Rashid bin Mohd Yusoff ◽  
Matyas Daboczi ◽  
Julio Conforto ◽  
Anderson Emanuel Ximim Gavim ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
High Mobility ◽  
Organic Light Emitting Diodes ◽  
Triplet Energy ◽  
Material Interface ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Hole Transporting

AbstractBlue organic light-emitting diodes require high triplet interlayer materials, which induce large energetic barriers at the interfaces resulting in high device voltages and reduced efficiencies. Here, we alleviate this issue by designing a low triplet energy hole transporting interlayer with high mobility, combined with an interface exciplex that confines excitons at the emissive layer/electron transporting material interface. As a result, blue thermally activated delay fluorescent organic light-emitting diodes with a below-bandgap turn-on voltage of 2.5 V and an external quantum efficiency (EQE) of 41.2% were successfully fabricated. These devices also showed suppressed efficiency roll-off maintaining an EQE of 34.8% at 1000 cd m−2. Our approach paves the way for further progress through exploring alternative device engineering approaches instead of only focusing on the demanding synthesis of organic compounds with complex structures.

Four color stacked white organic light-emitting diodes utilizing the concept of triplet harvesting

2011 ◽  
Vol 1286 ◽  
Author(s):  
Th. C. Rosenow ◽  
S. Olthof ◽  
S. Reineke ◽  
B. Lüssem ◽  
K. Leo
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Organic Light Emitting Diodes ◽  
Light Sources ◽  
Emission Layer ◽  
Light Emitting ◽  
Organic Light ◽  
Blue Emitters ◽  
Color Rendering ◽  
Triplet Harvesting

ABSTRACTOrganic light-emitting diodes (OLEDs) are developing into a competitive alternative to conventional light sources. Nevertheless, OLEDs need further improvement in terms of efficiency and color rendering for lighting applications. Fluorescent blue emitters allow deep blue emission and high stability, while phosphorescent blue emitter still suffer from insufficient stability. The concept of triplet harvesting is the key for achieving internal quantum efficiencies up to 100 % and simultaneously benefiting from the advantages of fluorescent blue emitters. Here, we present a stacked OLED consisting of two units comprising four different emitters in total. The first unit takes advantage of the concept of triplet harvesting and combines the light emission of a fluorescent blue and a phosphorescent red emitter. The second unit emits light from a single emission layer consisting of a matrix doped with phosphorescent green and yellow emitters. With this approach, we reach white color coordinates close to the standard illuminant A and a color rendering index of above 75. The presented devices are characterized by high luminous efficacies of above 30 lm/W on standard glass substrates without outcoupling enhancement.

Lowest unoccupied molecular orbital managing function of CN-substituted dibenzofuran in high triplet energy hosts for blue thermally-activated delayed fluorescent organic light-emitting diodes

2021 ◽  
Author(s):  
Sung Yong Byun ◽  
Kyung Hyung Lee ◽  
Jun Yeob Lee
Keyword(s):  
Molecular Orbital ◽  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Triplet Energy ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Lowest Unoccupied Molecular Orbital

The effect of lowest unoccupied molecular orbital (LUMO) management of high triplet energy electron transport type hosts on the device performance of blue thermally-activated delayed fluorescence (TADF) organic light-emitting diodes...

scholarly journals Pure exciplex-based white organic light-emitting diodes with imitation daylight emissions

RSC Advances ◽  
2018 ◽  
Vol 8 (53) ◽  
pp. 30582-30588 ◽  
Author(s):  
Dian Luo ◽  
Chung-Tsung Hsieh ◽  
Yen-Po Wang ◽  
Thomas C. Chuang ◽  
Hsin-Hua Chang ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light ◽  
Hole Transporting ◽  
White Oleds ◽  
Hole Transporting Material

Three hole-transporting material (HTM)/electron-transporting material (ETM) combinations are chosen to generate blue, green and red exciplexes, allowing us to design precise device architectures for the fabrication of exciplex-based white OLEDs with daylight-like emissions.

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