Highly Efficient Blue OLEDs Based on Metal‐Assisted Delayed Fluorescence Pd(II) Complexes
Highly Efficient Blue OLEDs Based on Metal‐Assisted Delayed Fluorescence Pd(II) Complexes
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DOI：
10.1002/adom.201801518
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发表时间：
2019-01
影响因子：
9
通讯作者：
Zhi‐Qiang Zhu;Choong-Do Park;Kody Klimes;Jian Li
中科院分区：
文献类型：
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作者：
Zhi‐Qiang Zhu;Choong-Do Park;Kody Klimes;Jian Li
研究了一系列金属辅助延迟荧光 (MADF) 钯 (II) 配合物、PdN1N、PdN1N-dm 和 PdN6N。它们的 77 K 光致发光发射光谱分别在 464、466 和 470 nm 处显示出狭窄的主发射峰，并具有许多磷光发射体的小振动峰特征。在室温 (300 K) 下，PdN1N、PdN1N-dm 和 PdN6N 的主发射峰分别轻微红移至 472、470 和 476 nm。同时，由于 MADF 工艺，410 至 450 nm 之间还显示出宽边带。采用 PdN1N-dm 的蓝色器件在 476 nm 处表现出电致发光发射峰，最大外量子效率 (EQE) 为 25.1%。蓝色有机发光二极管（OLED）器件的高最大EQE表明磷光和延迟荧光都非常有效。此外，稳定的 PdN1N-dm OLED 器件在 100 cd m−2 的实际亮度下，最大 EQE 为 9.8%，预计工作寿命 LT70 为 350 小时。
A series of metal‐assisted delayed fluorescence (MADF) palladium(II) complexes, PdN1N, PdN1N‐dm, and PdN6N, are studied. Their 77 K photoluminescence emission spectra show a narrow primary emission peak at 464, 466, and 470 nm, respectively, with small vibronic peaks characteristic of many phosphorescent emitters. At room temperature (300 K), the dominant emission peaks for PdN1N, PdN1N‐dm, and PdN6N are slightly redshifted to 472, 470, and 476 nm, respectively. In the meantime, a broad sideband is also shown between 410 and 450 nm due to the MADF process. A blue device employing PdN1N‐dm demonstrates an electroluminescence emission peak at 476 nm and the maximum external quantum efficiency (EQE) of 25.1%. The high maximum EQE of the blue organic light‐emitting diode (OLED) device indicates that both the phosphorescence and the delayed fluorescence are very efficient. In addition, a stable OLED device of PdN1N‐dm gives a maximum EQE of 9.8% and the estimated operational lifetime LT70 of 350 h at the practical luminance of 100 cd m−2.