Yun Jinyoung, Kim Jaeyun, Jung Byung Jun, Kim Gyutae, Kwak Jeonghun
School of Electrical Engineering, Korea University Seoul 02841 South Korea
School of Electrical and Computer Engineering, University of Seoul Seoul 02504 South Korea.
RSC Adv. 2019 May 24;9(28):16252-16257. doi: 10.1039/c9ra02946j. eCollection 2019 May 20.
High power efficiency (PE) and stability of quantum dot (QD) light-emitting diodes (QLEDs) are important factors for practical use in various displays. However, hybrid QLEDs consisting of an organic hole transport layer (HTL) and an inorganic electron transport layer (ETL) sometimes have poor stability due to the low thermal stability of the organic HTL. To solve the problem, here, we report enhanced efficiency, lifetime, and temperature stability in inverted and hybrid structured QLEDs by adopting a MoO-doped HTL. Also, to improve the electron-hole charge carrier balance, a thin insulating interlayer was used between QDs and the ETL. As a result, the QLED with the p-doped HTL exhibited the increased PE by ∼28% and longer lifetime compared to the pristine QLEDs. In addition, the QLED showed stable operation at the high temperature up to 400 K, whereas the control device failed to operate at 375 K. We systematically investigated the effect of the MoO-doping on the performance and thermal stability of the QLEDs. We believe that QLEDs with the p-doped HTL can be used for further QLED researches to simultaneously improve the efficiency, lifetime, and high temperature stability, which are highly required for their use in automotive and outdoor displays.
高功率效率（PE）和量子点（QD）发光二极管（QLED）的稳定性是其在各种显示器中实际应用的重要因素。然而，由有机空穴传输层（HTL）和无机电子传输层（ETL）组成的混合QLED有时由于有机HTL的低热稳定性而具有较差的稳定性。为了解决这个问题，在此我们报告通过采用MoO掺杂的HTL，在倒置和混合结构的QLED中提高了效率、寿命和温度稳定性。此外，为了改善电子 - 空穴电荷载流子平衡，在量子点和ETL之间使用了一层薄的绝缘中间层。结果，与原始QLED相比，具有p型掺杂HTL的QLED的功率效率提高了约28%，并且寿命更长。此外，该QLED在高达400 K的高温下表现出稳定的运行，而对照器件在375 K时就无法运行。我们系统地研究了MoO掺杂对QLED性能和热稳定性的影响。我们相信，具有p型掺杂HTL的QLED可用于进一步的QLED研究，以同时提高效率、寿命和高温稳定性，这些对于其在汽车和户外显示器中的应用是非常必要的。
