High-performance azure blue quantum dot light-emitting diodes via doping PVK in emitting layer
High-performance azure blue quantum dot light-emitting diodes via doping PVK in emitting layer
复制标题
发光层掺杂PVK的高性能天蓝色量子点发光二极管
DOI：
10.1016/j.orgel.2016.06.032
复制
发表时间：
2016-10-01
影响因子：
3.2
通讯作者：
Li, Lin Song
中科院分区：
文献类型：
--
作者：
Wang, Lei;Chen, Tao;Li, Lin Song
通过采用Zncdse Core/Multishell QD作为发射器，我们在这里报告的ZnCDSE Core/Multishell QD已证明了高度明亮有效的Azure蓝色量子点发射二极管（QD-LED），我们在这里报告的关键发展是可以通过掺杂来大大提高效率和明亮性的能力。发射层中的聚乙烯基（N-甲基唑）（PVK），以平衡电荷注入。最佳设备显示出了显着的特征，例如13,800 CD/M（2）的最大亮度，6.41 CD/A的发光效率和8.76％的外部量子效率（EQE），无可检测到的红移和电动发光（EL）光谱宽阔随着电压的增加以及光致发光（PL）和EL之间的良好光谱匹配。与没有PVK的QD-LED相比，这种Azure蓝色量子点LED显示外部量子效率提高了140％。更重要的是，以约1000 cd/m（2）的亮度实现了QD-LED的峰值效率，并且可以保持高效率（EQE> 8％），亮度范围为200至2400 cd/m （2）。 PVK在拟议系统中的作用有两个主要方面。首先，PVK的较低同性与仅使用TFB的HTL相比，可以导致较高的孔注入效率以及良好的EQE。 TFB和QD的缓冲层，可以有效改善从有机宿主到QD的激子能量转移（C）2016 Elsevier B.V.
Highly bright and efficient azure blue quantum dot-based light-emitting diodes (QD-LEDs) have been demonstrated by employing ZnCdSe core/multishell QDs as emitters and the crucial development we report here is the ability to dramatically enhance the efficiency and brightness through doping poly vinyl(N-carbazole) (PVK) in the emissive layer to balance the charge injection. The best device displays remarkable features like maximum luminance of 13,800 cd/m(2), luminous efficiency of 6.41 cd/A, and external quantum efficiency (EQE) of 8.76%, without detectable red-shift and broadening in electroluminescence (EL) spectra with increasing voltage as well as good spectral matching between photoluminescence (PL) and EL. Such azure blue quantum-dot LEDs show a 140% increase in external quantum efficiency compared with QD-LEDs without PVK. More important, the peak efficiency of the QD-LEDs with PVK dopant is achieved at luminance of about 1000 cd/m(2), and high efficiency (EQE > 8%) can be maintained with brightness ranging from 200 to 2400 cd/m(2). There are two main aspects of the role of PVK in the proposed system. Firstly, the lower HOMO of PVK than (poly[ 9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine] (TFB) can reduce the potential barrier for 0.4 eV at the interface of QDs and hole transport layer which could result in higher hole injection efficiency along with good EQE as compared to TFB-only HTLs. Secondly, with PVK acting as buffer layer of TFB and QDs, the exciton energy transfer from the organic host to the QDs can be effectively improved. (C) 2016 Elsevier B.V. All rights reserved.