High performance blue quantum dot light-emitting diodes employing polyethylenimine ethoxylated as the interfacial modifier

作者：Shi, Ying-Li; Liang, Feng; Hu, Yun; Zhuo, Ming-Peng; Wang, Xue-Dong^*; Liao, Liang-Sheng^*

来源：Nanoscale, 2017, 9(39): 14792-14797.

DOI：10.1039/c7nr04542e

• HIGH-EFFICIENCY
• TRANSPORT LAYERS
• DEVICES
• NANOCRYSTALS
• INJECTION
• DISPLAYS

Efficient electron-injection into the emitting layer (EML) plays a pivotal role in the fabrication of high performance blue quantum dot light-emitting diodes (QLEDs). Herein, we reduce the electron-transporting barrier at the ITO/ETL (electron-transporting layer) interface from 0.7 eV to 0.4 eV by spin-coating a polyethylenimine ethoxylated (PEIE) film (8 nm) on the ITO substrate. Meanwhile, the electron-injection barrier was reduced from 0.5 to 0.1 eV at the ETL/QD interface by employing the incorporation of PEIE (0.1 wt%) into a ZnO layer. These above two interfacial modifications jointly decrease the electron barrier and make the electron transportation easier. As a result, the optimized QLEDs with the 460 nm emission peak exhibit a maximum external quantum efficiency (EQE) of 7.85%, which is enhanced by 1.4 fold compared with the reference device (5.68%). It is demonstrated that the facile interfacial modification by the organic polymer PEIE contributes to the fabrication of high-efficiency blue QLEDs.

• 出版日期2017-10-21
• 单位苏州大学