High Performance Quantum Dot LEDs Enabled by Small‐Molecule Incorporation Within Emissive Layer

Quantum‐dot light‐emitting diodes (QLEDs) are commonly limited by imbalanced electron–hole transport and the resulting charge accumulation within the emissive layer. Here, we employ the Langmuir–Blodgett (LB) transfer technique to incorporate the small molecule 1,3‐bis( N ‐carbazolyl)benzene (mCP) into the QD emissive layer, constructing a QD–mCP hybrid emissive layer to synergistically regulate QD structural organization and local carrier transport. At the optimized QD:mCP mass ratio of 10:1, the device achieves an external quantum efficiency of 36.7%, a current efficiency of 58.5 cd A − 1 , and a power efficiency of 89.3 lm W − 1 , while maintaining a pure‐red emission peak at 622 nm with a full width at half maximum of 17.71 nm. The extrapolated T 95 lifetime reaches 35 064.6 h at 1000 cd m − 2 , more than three times that of the control device. These results demonstrate that the synergistic effects of LB‐directed QD structural regulation and mCP‐mediated carrier regulation play an important role in achieving highly efficient and stable QLEDs. This work provides a promising, simple, and low‐cost design strategy for developing high‐performance QLEDs with high efficiency, high color purity, and long operational lifetime.