Achieving Highly Efficient and Stable Quantum Dot Light-Emitting Diodes With Interface Modification
Fengqing Tian, Yangbin Zhu, Zhongwei Xu, Baoyu Li, Xiaojing Zheng, Ziquan Ni, Hailong Hu, Ying Chen, Jinyong Zhuang, Longjia Wu, Dong Fu, Xiaolin Yan, Fushan Li
Abstract
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 Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> 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 Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> interlayer plays a significant role in decreasing leakage current, suppressing exciton quenching and passivating the defects. The device with Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> interface modification exhibits the maximum external quantum efficiency (EQE) of 20.8%, current efficiency (CE) of 21.6 cd A <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , 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 Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> interface modification could provide an effective way for realizing highly efficiency QLED with long lifetime.