Dipole-Tunable Interfacial Engineering Strategy for High-Performance All-Inorganic Red Quantum-Dot Light-Emitting Diodes

All-inorganic quantum dot (QD) light-emitting diodes (AI-QLEDs) with excellent stability received enormous interest in the past few years. Nevertheless, the vast energy offset and the high trap density at the NiOX/QDs interface limit hole injection leading to fluorescence quenching and hampering the performance. Here, we present self-assembled monolayers (SAMs) with phosphonic acid (PA) anchoring groups modifying NiOXhole transport layer (HTL) to tune energy level and passivate trap states. This strategy facilitates hole injection owning to the well-aligned energy level by interface dipole, downshifting the vacuum level, reducing the hole injection barrier from 0.94eV to 0.28eV. Meanwhile, it mitigates the interfacial recombination by passivating surface hydroxyl group (-OH) and oxygen vacancy (VO) traps in NiOX. The electron leakage from QDs toward NiOXHTL is significantly suppressed. The all-inorganic R-QLEDs exhibit one of the highest maximum luminance, external quantum efficiency and operational lifetime of 88980cdm−2, 10.3% and 335045h (T50@100cdm−2), respectively. The as-proposed interface engineering provides an effective design principle for high-performance AI-QLEDs for future outdoor and optical projection-type display applications.