Enhancing the Performance of Blue Quantum-Dot Light-Emitting Diodes Based on Mg-Doped ZnO as an Electron Transport Layer

Highly efficient blue quantum-dot light-emitting diodes (QD-LEDs) have been fabricated by substituting Mg-doped ZnO (Mg
_x
Zn
_1-x
O) for ZnO as an electron transporting layer (ETL). The device performance can be enhanced by optimizing Mg-doped ratios for the device structure of ITO/PEDOT:PSS/PVK/QDs/Mg
_x
Zn
_1-x
O/Al. The maximum luminescence efficiency and maximum brightness of blue QD-LEDs increase from 1.1 cd/A and 1500 cd/m
²
for ZnO to 2.3 cd/A and 2500 cd/m
²
for 10% Mg-doped ZnO (Mg
_0.10
Zn
_0.90
O), respectively. The improved device performance should be attributed to balance electron and hole injection due to Mg-doped ZnO increasing the band gap and reduce exciton loss at the interface between the ETL and the emissive layer.