Recent Progress in Quantum Dot Light-Emitting Diodes: Degradation Mechanisms and Strategies for Improving Device Stability and Reliability

Quantum dot light-emitting diodes (QLEDs) employing quantum dots (QDs) as the emissive layer have emerged as pivotal devices for next-generation solution-processed printed displays. However, they encounter significant commercialization challenges due to operational instability and unpredictable shelf-storage behavior. This instability manifests as a complex luminance evolution, characterized by an initial increase (positive aging) followed by irreversible decay (intrinsic degradation) under electrical stress. Furthermore, uncontrolled efficiency enhancement during shelf storage leads to notable performance inconsistencies across different batches. A comprehensive understanding of the various mechanisms in QLEDs during operation and storage is essential for simultaneously improving stability and reliability. Consequently, this review systematically summarizes recent advances in the mechanisms underlying operation-induced positive aging and intrinsic degradation, and shelf-storage-induced positive aging of QLEDs. It is also highlighted how cutting-edge characterization techniques, such as in situ electrical/optical spectroscopy, electrically excited transient absorption spectroscopy, and impedance spectroscopy, provide critical insights into degradation processes beyond the capabilities of conventional methods. Furthermore, corresponding strategies are concluded to mitigate aging and enhance operational lifetime, ranging from material engineering to device architecture optimization, which provide a guideline for fabricating shelf-stable QLEDs with long operational lifetimes.