Chen Guo, Liu Feiyang, Ling Zhitian, Zhang Pengpeng, Wei Bin, Zhu Wenqing
Key Laboratory of Advanced Display and System Applications, Shanghai University, Ministry of Education, Shanghai, China.
Front Chem. 2019 Apr 16;7:226. doi: 10.3389/fchem.2019.00226. eCollection 2019.
In this study, we demonstrate highly efficient, inverted organic light-emitting diodes (IOLEDs) using solution-processed alkali metal carbonate doped ZnO as an electron injection layer (EIL) and tris-(8-hydroxyquinoline) aluminum (Alq) as an emitter layer. In order to enhance the electron injection efficiency of the IOLEDs, the ZnO EIL layers were modified by doping various alkali metal carbonate materials, including LiCO, NaCO, KCO, and CsCO, using the low-temperature wet-chemical method. Compared to the control neat ZnO EIL-based IOLEDs, the alkali metal carbonate doped ZnO EIL-based IOLEDs possess obviously improved device performance. An optimal current efficiency of 6.04 cd A were realized from the KCO doped ZnO EIL based IOLED, which is 54% improved compared to that of the neat ZnO EIL based device. The enhancement is ascribed to the increased electron mobility and reduced barrier height for more efficient electron injection. Our results indicate that alkali metal carbonate doped ZnO has promising potential for application in highly efficient solution-processed OLEDs.
在本研究中，我们展示了一种高效的倒置有机发光二极管（IOLED），它使用溶液处理的碱金属碳酸盐掺杂的ZnO作为电子注入层（EIL），并使用三（8 - 羟基喹啉）铝（Alq）作为发光层。为了提高IOLED的电子注入效率，采用低温湿化学方法，通过掺杂包括LiCO、NaCO、KCO和CsCO在内的各种碱金属碳酸盐材料对ZnO EIL层进行了改性。与基于纯ZnO EIL的对照IOLED相比，基于碱金属碳酸盐掺杂ZnO EIL的IOLED具有明显改善的器件性能。基于KCO掺杂ZnO EIL的IOLED实现了6.04 cd/A的最佳电流效率，与基于纯ZnO EIL的器件相比提高了54%。这种增强归因于电子迁移率的增加和势垒高度的降低，从而实现了更高效的电子注入。我们的结果表明，碱金属碳酸盐掺杂的ZnO在高效溶液处理OLED中具有广阔的应用前景。
