Achieving Highly Efficient and Stable Quantum Dot Light-emitting Diodes with Interface Modification

In conventional quantum dot light-emitting diodes (QLEDs), the organic charge transport materials are susceptible to erosion by water and oxygen, which would reduce the efficiency and lifetime of the devices. Herein, we modified the surface of the organic hole transport layer with an ultra-thin Al2O3 layer, which is deposited by using atomic layer deposition technique, to obtain the highly efficient and stable QLEDs. It is indicated that the ultra-thin Al2O3 interlayer plays a significant role in decreasing leakage current, suppressing exciton quenching and passivating the defects. The device with Al2O3 interface modification exhibits the maximum external quantum efficiency (EQE) of 20.8%, current efficiency (CE) of 21.6 cd A−1, and lifetime of 482000 h. In comparison with the control device, the EQE, CE and lifetime are improved by 31%, 32%, and 330%, respectively. The results indicate that the strategy of Al2O3 interface modification could provide an effective way for realizing highly efficiency QLED with long lifetime.