High-Resolution Submonolayer Quantum Dot Light-Emitting Devices

The multi-layer quantum dot (QD) stacking is prone to impairing intralayer charge transport between quantum wells, leading to inferior efficiency of QD light-emitting devices (QLEDs), especially in pixelated devices exposed to non-uniform electric fields. Herein, we propose an innovative strategy to rationally construct sub-monolayer QD emissive layers for high-resolution QLEDs through Langmuir-Blodgett assembly. In this design, reducing thickness of densely packed QDs eliminates the carrier transport barrier within the emission layer. Additionally, the strategic introduction of insulating nanoparticles generates localized electrostatic fields, enabling these nanoparticles to act as embedded nanocapacitors that significantly enhance hole injection under low-bias conditions. Consequently, the resultant high-resolution QLEDs (exceeding 10,000 pixels per inch) achieve a record external quantum efficiency (EQE) of 25.3% and power efficiency (PE) of 45.5 lm/W, which are significantly superior to those of the control counterparts (EQE = 17.6%, PE = 27.9 lm/W).