Exploring the Blue Quantum‐Dot Light‐Emitting Diode Degradation Using Time‐Resolved Electroluminescence Mapping

Abstract The poor stability of blue quantum‐dot light‐emitting diodes (QLEDs) hinders their commercial adoption. To reveal the degradation mechanism, a time‐resolved electroluminescence (TREL) mapping technology is developed to track the positive and negative degradation processes. An inhomogeneous initial brightness distribution on the QLED luminescent surface is observed, attributed to inhomogeneous electron injection, which is gradually eliminated during the positive degradation process. By treating each pixel on the QLED as an individual mini‐QLED, substantial data is obtained for statistical analysis, elucidating the relationship between device degradation and carrier injection dynamics in QLEDs. Both positive and negative degradation processes are found to be correlated with hole injection efficiency. Results indicate that positive degradation arises from enhanced hole injection due to increased electron accumulation in the QDs, while negative degradation results from hole transport layer deterioration that reduces hole injection efficiency. These findings contribute a novel perspective for the development of stable blue QLEDs.