Mimicking Positive Aging using Atomic Layer Deposition of Alumina in Quantum Dot Light-Emitting Diodes

Quantum dot light-emitting diodes (QD-LEDs) frequently exhibit a unique characteristic known as positive aging, where their efficiency improves over time. In this study, we delve into the underlying causes of this behavior. Our findings suggest that the densification of the ZnMgO electron transport layer plays a pivotal role in this process. As the device undergoes shelf-aging, ZnMgO nanoparticles coalesce, leading to a reduction in leakage current and a decrease in surface vacancies within the ZnMgO layer. To expedite the device's performance without waiting for the positive aging effect, we introduced an Al₂O₃ layer via atomic layer deposition between the ZnMgO and the electrode. This modification resulted in red InP QD-LEDs showcasing a remarkable 1.3-fold boost in efficiency and a tenfold enhancement in stability, underscoring the potential of the Al₂O₃ layer in optimizing QD-LED performance.