@article{Xu2022, 
author = {Maopeng Xu and Desui Chen and Jian Lin and Xiuyuan Lu and Yunzhou Deng and Siyu He and Xitong Zhu and Wangxiao Jin and Yizheng Jin},
title = {Quantum-dot light-emitting diodes with Fermi-level pinning at the hole-injection/hole-transporting interfaces},
year = {2022},
journal = {Nano Research},
volume = {15},
number = {8},
pages = {7453-7459},
keywords = {quantum-dot light-emitting diodes, Fermi-level pinning, hole-injection/hole-transporting interfaces, work function, performance},
url = {https://www.sciopen.com/article/10.1007/s12274-022-4260-3},
doi = {10.1007/s12274-022-4260-3},
abstract = {Quantum-dot light-emitting diodes (QLEDs) are multilayer electroluminescent devices promising for next-generation display and solid-state-lighting technologies. In the state-of-the-art QLEDs, hole-injection layers (HILs) with high work functions are generally used to achieve efficient hole injection. In these devices, Fermi-level pinning, a phenomenon often observed in heterojunctions involving organic semiconductors, can take place in the hole-injection/hole-transporting interfaces. However, an in-depth understanding of the impacts of Fermi-level pinning at the hole-injection/hole-transporting interfaces on the operation and performance of QLEDs is still lacking. Here, we develop a set of NiOx HILs with controlled work functions of 5.2–5.9 eV to investigate QLEDs with Fermi-level pinning at the hole-injection/hole-transporting interfaces. The results show that despite that Fermi-level pinning induces identical apparent hole-injection barriers, the red QLEDs using HILs with higher work functions show improved efficiency roll-off and better operational stability. Remarkably, the devices using the NiOx HILs with a work function of 5.9 eV demonstrate a peak external quantum efficiency of ~ 18.0% and a long T95 operational lifetime of 8,800 h at 1,000 cd·m−2, representing the best-performing QLEDs with inorganic HILs. Our work provides a key design principle for future developments of the hole-injection/hole-transporting interfaces of QLEDs.}
}