Electric-Healing Process of Calendar-Aged Quantum Dot Light-Emitting Diodes

Quantum-dot light-emitting diodes (QD-LEDs) have shown great promise for high-efficiency luminescence applications. However, the underlying mechanisms of long-term storage-induced degradation (calendar-aged) and electric-healed behavior remain not fully understood. In this study, the truth behind the calendar aging and subsequent electric-healing behavior of QD-LEDs is revealed by means of multiple characterizations. The results show that the performance degradation of calendar-aged devices originates from the significant reduction of the electron injection efficiency. Specifically, the irregular chemical degradation of the zinc oxide (ZnO) electron transport layer increases electronic defect states, leading to electron trapping along the injection path and a reduction in exciton formation. However, the calendar-aged device fills the defective state under the electric field to recover luminance, efficiency, and light-emitting uniformity. This study highlights the essential role of electron transport layer stability in QD-LED performance, revealing the mechanisms behind electrical healing and offering key insights for developing more efficient and stable sandwich structured optoelectronic devices.