Ultrapure Blue Thermally Activated Delayed Fluorescence Molecules: Efficient HOMO–LUMO Separation by the Multiple Resonance Effect

Abstract

Ultrapure blue-fluorescent molecules based on thermally activated delayed fluorescence are developed. Organic light-emitting diode (OLED) devices employing the new emitters exhibit a deep blue emission at 467 nm with a full-width at half-maximum of 28 nm, CIE coordinates of (0.12, 0.13), and an internal quantum efficiency of ≈100%, which represent record-setting performance for blue OLED devices.

Thermally Activated Delayed Fluorescence Emitters for Deep Blue Organic Light Emitting Diodes: A Review of Recent Advances

“…Some of them even show CIE coordinates of (0.15, 0.09) and (0.15, 0.08) for the PL of emitters in toluene but none of them gave OLEDs with colour coordinates satisfying or being close to the NTSC blue standard of CIE coordinates (0.14, 0.08) [94]. Recently, Hatakeyama et al reported a new strategy to design effective deep blue triarylboron based emitters [95]. The chemical structures of boron emitters (28)(29) are given in Figure 6, while their novel design strategy is displayed in Figure 7.…”

Pyrimidine-based twisted donor–acceptor delayed fluorescence molecules: a new universal platform for highly efficient blue electroluminescence

“…However, high-performance blue TADF emitters are still very rare and only a few of them can achieve both a high external EL quantum efficiency ( η ext ) exceeding 20% and a suitable color purity with a CIE y value below 0.25. 10,16,21,22,29,33,34,38 Hence, it remains quite challenging to search for an appropriate combination of D and A moieties to simultaneously attain both excellent EL efficiency and high color purity for deep-blue TADF materials.…”

Recent progress of pyrimidine derivatives for high-performance organic light-emitting devices

“…12). [82][83][84] A representative example of 9-([1,1′-biphenyl]-3-yl)-N,N,5,11-tetraphenyl-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracen-3-amine (DABNA-2) developed by Hatakeyama et al 82 realized a high EQE of 20% and a very narrow full-width at half-maximum of 28 nm. Furthermore, Mamada et al 83 presented a whole new type of planar TADF emitter based on the use of excitedstate intramolecular proton transfer without conventional D-A structures.…”