Inverted Quantum-Dot Light-Emitting Diodes with WO3/Zinc-Tin-Oxide Electron Transporting Layers

We demonstrate the enhanced efficiency of inorganic/organic hybrid quantum-dot light-emitting diodes (QD-LEDs) by adopting WO
₃
/zinc-tin-oxide (ZTO) as an electron-transporting layer (ETL). The relationship between the ETL properties and device performance was explained by the effect of the WO
₃
layer on electron transport, which was investigated using thin film analysis methods. A maximum luminance of 700 cd/m
²
and current efficiency of 0.43 cd/A were obtained from a QD-LED with 40-nm-thick WO
₃
. The current efficiency was more than twice that of a device without a WO
₃
layer.