Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM) , Soochow University , Suzhou , Jiangsu 215123 , China.
ACS Appl Mater Interfaces. 2018 Nov 14;10(45):39116-39123. doi: 10.1021/acsami.8b17737. Epub 2018 Nov 1.
It is a challenge to engineer white organic light-emitting diodes (WOLEDs) with high efficiency, low operating voltage, good color quality, and low efficiency roll-off, simultaneously. Herein, we employ a novel exciplex to solve this problem, which mixes a bipolar host material 2,6-bis(3-(carbazol-9-yl)phenyl)pyridine (26DCzPPy) with a common electron-transporting material 4,6-bis[3,5-(dipyrid-4-yl)phenyl]-2-methylpyrimidine (B4PyMPM) to form the host for a blue emitter iridium(III)bis(4,6-(difluorophenyl)-pyridinato- N,C') picolinate (FIrpic). The blue OLED with maximum power efficiency (PE) over 48 lm W and Commission International de I'Eclairage chromaticity diagram (0.17, 0.36) was achieved. To obtain white light emission, a complementary orange emission layer is used, which consists of the bis(4-phenylth-ieno[3,2- c]pyridine)(acetylacetonate)iridium(III) (PO-01) doped into the single host of 26DCzPPy adjacent to the blue emission layer. Benefiting from the exciplex and effective utilization of the excitons by using the optimized multifunctional device structure, the WOLEDs remarkably exhibit maximum external quantum efficiency, PE, and current efficiency of 28.5%, 95.5 lm W, and 82.0 cd A, respectively. At the luminance of 100 cd m, it maintains the values of 27.2%, 90.2 lm W, and 78.4 cd A, respectively. Furthermore, the WOLEDs have a low threshold voltage of about 2.6 V and remain around 4.0 V at 10 000 cd m. These results indicate that the exciplex-forming co-host 26DCzPPy:B4PyMPM can provide an effective strategy to fabricate high-efficiency WOLEDs for potential applications.
同时实现高效率、低工作电压、良好的颜色质量和低效率滚降的白色有机发光二极管（WOLED）的工程设计是一个挑战。在此，我们采用一种新型的激基复合物来解决这个问题，该激基复合物将双极主体材料 2,6-双（3-（咔唑-9-基）苯基）吡啶（26DCzPPy）与常见的电子传输材料 4,6-双[3,5-（二吡啶-4-基）苯基]-2-甲基嘧啶（B4PyMPM）混合，形成蓝色发射器铱（III）双（4,6-（二氟苯基）-吡啶并[2,3-d]嘧啶- N,C'）吡啶甲酸酯（FIrpic）的主体。具有超过 48 lm W 的最大功率效率（PE）和国际照明委员会色度图（0.17,0.36）的蓝色 OLED 得以实现。为了获得白光发射，使用互补的橙色发射层，该橙色发射层由双（4-苯基噻吩并[3,2-c]吡啶）（乙酰丙酮）铱（III）（PO-01）掺杂到靠近蓝色发射层的 26DCzPPy 单一主体中组成。得益于激基复合物和通过优化的多功能器件结构有效利用激子，WOLED 显著表现出 28.5%、95.5 lm W 和 82.0 cd A 的最大外量子效率、PE 和电流效率。在亮度为 100 cd m 时，它们分别保持 27.2%、90.2 lm W 和 78.4 cd A 的值。此外，WOLED 的阈值电压约为 2.6 V，在 10000 cd m 时约为 4.0 V。这些结果表明，形成激基复合物的共主体 26DCzPPy:B4PyMPM 可为制造高效率 WOLED 提供有效策略，具有潜在的应用前景。
