Efficient and Long Lifetime Red InP‐Based QLEDs Enabled by Simultaneously Improved Carrier Injection Balance and Depressed Leakage

Abstract InP quantum dots (QDs), without heavy metals, show great potential for display and lightening applications. However, achieving efficient InP‐based quantum dot light‐emitting diodes (QLEDs) with extended operational lifetime remains challenging due to unbalanced carrier injection within the device. In this study, polyvinyl pyrrolidone (PVP) is introduced as an intermediate layer between the QDs emitting layer (EML) and the ZnMgO electron transport layer (ETL). This intermediate layer is designed to block excess electron injection into the QDs layer and simultaneously reduce leakage current. Additionally, the introduction of PVP can passivate QDs/ETL interface defects and inhibit exciton quenching of QDs by the ZnMgO ETL. The optimized device achieves a peak external quantum efficiency (EQE) of 23.5% and a long T 95 operational lifetime of over 800 h at an initial luminance of 1000 cd m −2 for red InP‐based QLEDs emitting at 624 nm. Both the EQE and the T 95 operational lifetime represent the highest values achieved for red InP‐based QLEDs to date.