Conventional fluorescence-based organic light-emitting diodes (OLEDs) have attracted wide interest due to their long operational lifetime, high color purity, low efficiency roll-off and potential to be manufactured at low cost in the applications of next-generation full-color display and solid state lighting. However, the external quantum efficiency (EQE) of fluorescent OLEDs is limited to 5% due to the inability to use the generated triplet excitons. Here, we report a blue fluorescent OLED that realizes an EQE as high as 14.1% by using a thermally activated delayed fluorescent (TADF) material as an assistant host in the emitting layer, which permits the efficient energy transfer of all generated excitons to the blue fluorescent dopant. Furthermore, color-stable hybrid warm-white OLEDs with improved lifetime also have been obtained. The maximum forward-viewing power efficiency (PE), current efficiency (CE), and EQE are as high as 68.5 lm W⁻¹, 56.7 cd A⁻¹ and 20.1%, respectively, and the T₅₀ lifetime at L₀ = 1000 cd m⁻² reaches 1657 h. The achievement of these results fully exhibits the effectiveness of the TADF material as the assistant host to fabricate high efficiency and long lifetime fluorescent OLEDs.

中文翻译：

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基于热活化延迟荧光材料作为辅助基质的高效蓝色和颜色稳定的混合暖白有机发光二极管

常规的基于荧光的有机发光二极管（OLED）的长使用寿命，高色纯度，低效率滚降以及在下一代全彩色应用中以低成本制造的潜力备受关注。显示器和固态照明。但是，由于无法使用生成的三重态激子，荧光OLED的外部量子效率（EQE）限制为5％。在这里，我们报告了一种蓝色荧光OLED，它通过在发射层中使用热活化延迟荧光（TADF）材料作为辅助主体，实现了高达14.1％的EQE，从而可以将所有生成的激子有效地转移到蓝色荧光掺杂剂。此外，还已经获得了具有改善的寿命的颜色稳定的混合暖白OLED。^-1，56.7光盘^-1和分别20.1％，和Ť ₅₀在寿命大号₀ = 1000 CD米^-2达到1657小时。这些结果的实现充分展示了TADF材料作为制造高效和长寿命荧光OLED的辅助主体的有效性。