39.1:Invited Paper: Efficient Color Tunable Light Sources by The Combination of a Transparent and a Non-Transparent Organic Light Emitting Diodes

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.

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Transparent bi-directional organic light-emitting diodes with color-tunable top emission

Organic Electronics ◽

10.1016/j.orgel.2020.105900 ◽

2020 ◽

Vol 86 ◽

pp. 105900

Author(s):

Gunel Huseynova ◽

Jae-Hyun Lee ◽

Yong Hyun Kim ◽

Jonghee Lee

Keyword(s):

Light Emitting Diodes ◽

Organic Light Emitting Diodes ◽

Light Emitting ◽

Organic Light ◽

Color Tunable

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Flexible organic light-emitting diodes for antimicrobial photodynamic therapy

npj Flexible Electronics ◽

10.1038/s41528-019-0058-0 ◽

2019 ◽

Vol 3 (1) ◽

Cited By ~ 7

Author(s):

Cheng Lian ◽

Marta Piksa ◽

Kou Yoshida ◽

Saydulla Persheyev ◽

Krzysztof J. Pawlik ◽

...

Keyword(s):

Photodynamic Therapy ◽

Bacterial Infections ◽

Light Emitting Diodes ◽

High Irradiance ◽

Organic Light Emitting Diodes ◽

Light Sources ◽

Driving Voltage ◽

Light Emitting ◽

Organic Light ◽

Operational Lifetime

Abstract Bacterial infection and the growth of antibiotic resistance is a serious problem that leads to patient suffering, death and increased costs of healthcare. To address this problem, we propose using flexible organic light-emitting diodes (OLEDs) as light sources for photodynamic therapy (PDT) to kill bacteria. PDT involves the use of light and a photosensitizer to generate reactive oxygen species that kill neighbouring cells. We have developed flexible top-emitting OLEDs with the ability to tune the emission peak from 669 to 737 nm to match the photosensitizer, together with high irradiance, low driving voltage, long operational lifetime and adequate shelf-life. These features enable OLEDs to be the ideal candidate for ambulatory PDT light sources. A detailed study of OLED–PDT for killing Staphylococcus aureus was performed. The results show that our OLEDs in combination with the photosensitizer methylene blue, can kill more than 99% of bacteria. This indicates a huge potential for using OLEDs to treat bacterial infections.

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