Enhanced electroluminescence of all-inorganic colloidal quantum dot light-emitting diode by optimising the MoO3 intermediate layer

The effects of the molybdenum trioxide (MoO₃) intermediate layer on the performance of all-inorganic colloidal quantum dot light-emitting diodes (QD-LEDs) with a structure of ITO/MoO₃/NiO/QDs/ZnO/Al are explored. MoO₃ layers with different thickness were inserted between the indium tin oxide and nickel oxide layer via a thermal evaporation process. The presented results show that an ultrathin ( ~ 5 nm) MoO₃ intermediate layer significantly enhanced the electroluminescence (EL) intensity of the QD-LED, which was more than 100 times higher than the device without the MoO₃ layer. It is suggested that the EL enhancement originates from the effectively facilitated injection of holes into quantum dots through the MoO₃ intermediate layer.