Thermally Activated Delayed Fluorescence Warm White Organic Light Emitting Devices with External Quantum Efficiencies Over 30%
Thermally Activated Delayed Fluorescence Warm White Organic Light Emitting Devices with External Quantum Efficiencies Over 30%
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DOI：
10.1002/adfm.202101647
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发表时间：
2021-05-31
影响因子：
19
通讯作者：
Lee, Chun-Sing
中科院分区：
文献类型：
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作者：
Chen, Jia-Xiong;Wang, Kai;Lee, Chun-Sing
虽然基于热激活延迟荧光(TADF)发射器的单色有机电致发光二极管(OLED)已经达到了30%以上的外量子效率(EQE)，但全TADF白光OLED(WOLED)仍然落后。在此，开发了一种基于两个彩色互补TADF发射体的简单系统来实现高性能的WOLED。通过将高性能的橙红色TADF荧光体(BPPZ-DPXZ)掺杂到蓝色TADF主体(DBFCz-TRZ)中，可以优化主体-掺杂系统中的能量传递和三重态到单重态的转换，同时实现激子的充分利用和颜色平衡。该设计实现了全TADF单发光层WOLED，EQE最高可达32.8%。这种高效率超过了已报道的基于TADF和磷光的WOLED的EQE。期望这一发现能够为设计高效的全TADF WOLED提供新的见解。
While monochrome organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters have achieved over 30% external quantum efficiencies (EQEs), all-TADF white OLEDs (WOLEDs) are still lagging behind. Herein, a simple system based on two color-complementary TADF emitters is exploited to realize high-performance WOLEDs. By doping a high-performance orange-red TADF fluorophor (BPPZ-DPXZ) into a blue TADF host (DBFCz-Trz), energy transfer, and triplet-to-singlet conversion in the host-dopant system can be optimized to simultaneously achieve full exciton utilization and color balance. With this design, all-TADF single-emitting-layer WOLEDs with a maximum EQE up to 32.8% are demonstrated. This high efficiency surpasses EQEs of reported WOLEDs based on both TADF as well as phosphorescence. It is expected that this finding can provide new insight for designing highly efficient all-TADF WOLEDs.