High-Performance Blue Quantum Dot Light-Emitting Diodes via ZnSe-Engineered Core/Shell Quantum Dots

Quantum dot light-emitting diodes (QLEDs) have emerged as strong contenders for next-generation display technologies. However, the commercialization of blue QLEDs has been severely hindered by the inherent wide band gap of blue quantum dots (QDs), which results in a high hole injection barrier and imbalanced carrier injection. Herein, we demonstrate high-efficiency and high-luminance blue QLEDs by engineering gradient core/shell ZnCdSe/ZnSe/ZnSeS/ZnS QDs with a ZnSe intermediate shell layer. The ZnSe interlayer not only effectively passivates surface defects but also facilitates balanced carrier injection. This strategy achieves a remarkable maximum luminance of 54,554 cd m⁻² and an external quantum efficiency (EQE) of 20.6%, representing a significant advancement in device performance. This work provides a strategy for developing high-performance blue QLEDs.