High-Performance, Solution-Processed, and Insulating-Layer-Free Light-Emitting Diodes Based on Colloidal Quantum Dots (original) (raw)

Quantum-dot light-emitting diodes (QLEDs) may combine superior properties of colloidal quantum dots (QDs) and advantages of solution-based fabrication techniques to realize high-performance, large-area, and low-cost electroluminescence devices. In the state-of-the-art red QLED, an ultrathin insulating layer inserted between the QD layer and the oxide electron-transporting layer (ETL) is crucial for both optimizing charge balance and preserving the QDs' emissive properties. However, this key insulating layer demands very accurate and precise control over thicknesses at sub-10 nm level, causing substantial difficulties for industrial production. Here, it is reported that interfacial exciton quenching and charge balance can be independently controlled and optimized, leading to devices with efficiency and lifetime comparable to those of state-of-the-art devices. Suppressing exciton quenching at the ETL-QD interface, which is identified as being obligatory for high-performance device...