Quantum-dot light-emitting diodes with NiO and NiO:Mg as hole injection layer

Quantum-dot light-emitting diodes (QLED) have attracted great attention due to their impressive optoelectronic properties and stability. The most common used hole injection layer (HIL) material Poly(3,4-ethylenedioxytiophene):polystyrene sulfonate (PEDOT:PSS) is acidic and causes corrosion of indiumtin-oxide (ITO) anodes. Nickle oxide (NiO) are widely used as the hole transport layer (HTL) in QLED due to their suitable electrical properties. For the large energy gap between QD and HTL, there is unbalanced charge injection in QLED device when NiO is used. The energy band structures of NiO can be adjusted by Mg doping, which is an effective strategy to improve charge injection and mobility. Compared to undoped HIL, device with doped NiO give rise to higher EQE. In this work, our results suggests that Mg-doped NiO serve as a good hole injection layer materials for QLED and other optoelectronic devices.