Positive Aging in Quantum Dot Light-Emitting Diodes with Controllable Quantum Dot Assembly

Positive aging in quantum dot light-emitting diodes (QLEDs) is a common phenomenon, and its unpredictability is a serious problem for large size or high-resolution devices. In this work, the compact assembly of quantum dots (QDs) was realized by using Langmuir-Blodgett (LB) technology, and we propose a novel interactive mechanism for the positive aging of QLEDs based on the self-assembled QD film. We suggest that there is a quasi-monolayer phase between strictly solid phase and collapse during the LB process. The QD assembly states vary the external quantum efficiency (EQE) climbing process and the electroluminescent (EL) peak distribution during operation, as well as the aging rearrangement of QDs in the device. The tight alignment of QDs has low entropy and contributes to enhancing device stability. Our study contributes to the understanding of the origin of positive aging of QLEDs and holds potential for the practical application of QLEDs in displays.