Combining emissions of hole- and electron-transporting layers simultaneously for simple blue and white organic light-emitting diodes with superior device performance
Combining emissions of hole- and electron-transporting layers simultaneously for simple blue and white organic light-emitting diodes with superior device performance
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同时结合空穴传输层和电子传输层的发射，实现具有卓越器件性能的简单蓝色和白色有机发光二极管
DOI：
10.1039/c7tc05568d
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发表时间：
2018-02-21
影响因子：
6.4
通讯作者：
Xu, Bingshe
中科院分区：
文献类型：
--
作者：
Miao, Yanqin;Wang, Kexiang;Xu, Bingshe
采用简单的双层结构，研制了一种高效的深蓝色荧光有机电致发光二极管（OLED），其发射峰位于432 nm，亮度高达14 140 cd m（-2），外量子效率（EQE）为5.07%，超过了理论极限。通过同时组合空穴传输层4P-NPD和电子传输层Bepp 2的发射，实现了这种高器件性能。此外，基于上述4P-NPD/Bepp 2的蓝光发射，通过在4P-NPD和Bepp 2两侧方便地布置掺杂的互补磷光体，展示了一系列简单的双色、三色和四色混合白色OLED（WOLED），而无需在荧光和磷光发射层之间的夹层。这些混合WOLED实现了上级器件效率，优化的双色、三色和四色WOLED的最大EQE分别达到18.87%、15.49%和18.44%。此外，在83.68- 17050 cd·m（-2）的宽亮度范围内，四色混合WOLED还具有93-94的显色指数（CRI）。据我们所知，这是使用这种简单结构的非常高CRI WOLED的最佳效率之一。实现高器件性能进行了详细的探讨，并归因于通过提出的新的器件结构的单重态和三重态激子的精确管理和有效利用。
An efficient deep-blue fluorescent organic light-emitting diode (OLED), showing an emission peak at 432 nm, a high luminance of 14 140 cd m(-2), and an external quantum efficiency (EQE) of 5.07% (which exceeds the theoretical limit), was developed by employing a simple bilayer structure. Such high device performance was achieved by combining emissions of the hole-transporting layer 4P-NPD and the electron-transporting layer Bepp2, simultaneously. Furthermore, based on the blue emission of the above-mentioned 4P-NPD/Bepp2, by handily arranging complementary phosphors doped in both 4P-NPD and Bepp2 sides, a series of simple two-, three-, and four-color hybrid white OLEDs (WOLEDs) without the interlayer between fluorescent and phosphorescent emitting layers were demonstrated. These hybrid WOLEDs realize superior device efficiency, the maximum EQE reaching 18.87%, 15.49%, and 18.44% for optimized two-, three-, and four-color WOLEDs, respectively. Moreover, the four-color hybrid WOLED also exhibits a very high color rendering index (CRI) of 93-94 over a wide luminance range of 83.68-17 050 cd m(-2). To our knowledge, this is among the best efficiencies for very high CRI WOLEDs using such simple structures. The realization of high device performance was explored in detail, and was ascribed to the precise management and effective utilization of singlet and triplet excitons via the proposed novel device structure.