Lowering electron injection barrier via stepwise transport layer for high-performance blue inverted ZnSeTe QLEDs

Abstract

All-solution processed inverted quantum dot light-emitting diodes (QLEDs) have shown great promise for applications in lighting and display technologies. However, the practical deployment of eco-friendly blue inverted QLEDs remains a significant challenge, particularly in enhancing their luminous efficiency and operational stability. Herein, we report an eco-friendly, all-solution processed inverted blue QLEDs based on ZnSeTe quantum-dots, incorporating a ZnO interlayer within the electron transport layer to establish a stepwise double-layer electron transport structure. The ZnO interlayer effectively reduces the electron injection barrier between ITO and ZnMgO layers, thereby enhancing electron injection efficiency, promoting carrier recombination, and ultimately improving device performance. The experimental results reveal that ZnSeTe-based all-solution inverted blue QLEDs with the ZnO interlayer achieved a maximum external quantum efficiency of 6.1%, a peak brightness of 1862 cd m−2, and a T50 lifetime of 6.7 h at 1000 cd m−2. This study demonstrates the effectiveness of ZnO interlayer in improving the performance of eco-friendly all-solution inverted QLEDs and provides valuable insights for advancing eco-friendly QLED technology.