Inverted Quantum-Dot Light-Emitting Diodes with WO 3 /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.