Thermally activated delayed fluorescence (TADF) compounds
Electronics, Sensors & Photonics
The use of TADF emitters represents a paradigm shift in emitter development wherein inexpensive small molecule organic compounds can now be used to harvest 100% of the excitons in an electroluminescent device and so obtain excellent power efficiencies. We have developed a series of deep blue TADF emitters for Organic Light-Emitting Diodes (OLED).
TADF allows purely organic emitters to harvest the triplet states as an alternative to the existing heavy-metal based phosphorescent OLEDs, which are known to be expensive and environmentally hostile. The emitters contain both carbazole donors and oxadiazole acceptors to effectively form excitons by a charge trapping mechanism. The blue colour emission wavelength of these emitters can be a valuable asset as there is currently a dearth of bright blue-emitting phosphorescent emitters for OLEDs.
The invention is primarily used for blue-emitting OLEDs or, when operating in parallel with green and red emitters, for energy-efficient white lighting devices. Due to the nature of TADF, potential applications also include temperature or oxygen sensors.
- Harvesting 100% of excitons via TDF for OLED devices
- Inexpensive organic emitters
- Environmentally more benign
- Deep blue emission colour
- Ambipolar characteristic
- Blue-emitting OLEDs
- To operate in parallel with red and green emitters for energy efficient white light devices
- Due to the nature of TADF, potential applications also include temperature or oxygen sensors
Subject to UK patent application number 1507340.6 filed 29 April 2015.