Circularly Polarized Phosphorescent Electroluminescence with a High Dissymmetry Factor from PHOLEDs Based on a Platinahelicene
Circularly Polarized Phosphorescent Electroluminescence with a High Dissymmetry Factor from PHOLEDs Based on a Platinahelicene
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DOI：
10.1021/jacs.6b02463
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发表时间：
2016-08-10
影响因子：
15
通讯作者：
Fuchter, Matthew J.
中科院分区：
文献类型：
--
作者：
Brandt, Jochen R.;Wang, Xuhua;Fuchter, Matthew J.
圆偏振光在量子光学计算、光学自旋电子学、生物医学和高效率显示等领域具有重要的应用价值。从有机发光二极管(OLED)中直接发射CP光一直是研究的重点，因为它在基于OLED的显示器中具有提高效率和简化设备结构的直接应用。据报道，使用荧光聚合物的器件具有很高的不对称(EEL)因子值，但这些CP-OLED的最终效率受到所涉及的发射电子跃迁类型的限制。相比之下，磷光有机发光二极管(PHOLED)可以从三重激发态发光，因此可以实现非常高的效率。然而，对CP-PHOLED的研究严重不足，之前的两份报告都存在亮度或凝胶值非常低的问题。在这里，我们使用铂氢化合物来构建CP-PHOLED，它既能达到显示水平的亮度，又能获得高的凝胶系数。通过这种概念验证的单层螺烯器件实现的CP发射的不对称性足以提供比非极化发射更真实的好处，并为基于手性金属络合物的CP-PHOLED显示器铺平了道路。
Circularly polarized (CP) light is of interest in areas such as quantum optical computing, optical spintronics, biomedicine, and high efficiency displays. Direct emission of CP light from organic light-emitting diodes (OLEDs) has been a focus of research as it has the immediate application of increasing efficiency and simplifying device architecture in OLED based displays. High dissymmetry (EEL) factor values have been reported for devices employing fluorescent polymers, but these CP-OLEDs are limited in their ultimate efficiencies by the type of emissive electronic transitions involved. In contrast, phosphorescent OLEDs (PHOLEDs) can emit light from triplet excited states and can therefore achieve very high efficiencies. However, CP-PHOLEDs are significantly understudied, and the two previous reports suffered from very low brightness or gEL values. Here, we use a platinahelicene complex to construct a CP-PHOLED that achieves both a display level brightness and a high gEL factor. The dissymmetry of CP emission reached with this proof-of-concept single-layer helicene-based device is sufficient to provide real-world benefits over nonpolarized emission and paves the way toward chiral metal complex based CP-PHOLED displays.