Chen Yuwen, Ying Shian, Sun Qian, Dai Yanfeng, Qiao Xianfeng, Yang Dezhi, Chen Jiangshan, Ma Dongge
Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology Guangzhou 510640 People's Republic of China
RSC Adv. 2018 Dec 6;8(71):40883-40893. doi: 10.1039/c8ra08753a. eCollection 2018 Dec 4.
It is well-known that hybrid white organic light-emitting diodes (WOLEDs) are constructed by blue fluorophors and red-green or orange phosphors, therefore, theoretically exhibiting the advantages of long lifetime and high efficiency. However, the efficiency is far from reaching the expected values. Here, we designed a simple and efficient exciton regulation emissive layer (EML) structure to fabricate high efficiency hybrid WOLEDs. The EML sequentially comprises a yellow EML of phosphor doped hole-transporting material, a blue EML of a blend of hole- and electron-transporting materials and an exciton regulation layer of ultra-thin green phosphor inserted in electron-transporting material. It can be seen that the emissive excitons are well regulated by such a strategic EML structure. The resulting WOLEDs exhibit a maximum forward viewing external quantum efficiency and power efficiency of 18.2% and 72.9 lm W, respectively, and they are as high as 16.7% and 61.7 lm W at 100 cd m, and 12.5% and 37.7 lm W at 1000 cd m, showing the positive properties of high efficiency and low efficiency roll-off. Such outstanding performance will greatly promote the development of high performance hybrid WOLEDs.
众所周知，混合白色有机发光二极管（WOLED）由蓝色荧光体和红绿色或橙色磷光体构成，因此理论上具有长寿命和高效率的优点。然而，其效率远未达到预期值。在此，我们设计了一种简单高效的激子调控发光层（EML）结构来制备高效率混合WOLED。该EML依次包括磷光体掺杂空穴传输材料的黄色EML、空穴传输材料与电子传输材料混合物的蓝色EML以及插入电子传输材料中的超薄绿色磷光体激子调控层。可以看出，通过这种精心设计的EML结构，发光激子得到了很好的调控。所制备的WOLED的最大正向视角外量子效率和功率效率分别为18.2%和72.9 lm/W，在100 cd/m²时分别高达16.7%和61.7 lm/W，在1000 cd/m²时分别为12.5%和37.7 lm/W，展现出高效率和低效率滚降的良好特性。如此出色的性能将极大地推动高性能混合WOLED的发展。
