Interfacial Modification\nof ZnO/ZnMgO Bilayer for\nEfficient and Stable InP Quantum Dot Light-Emitting Diodes via Ultraviolet\nOzone Treatment

The development of efficient charge transport layers\nis crucial\nfor realizing high-performance and stable quantum dot light-emitting\ndiodes (QD-LEDs). The use of a ZnO/ZnMgO bilayer as an electron transporting\nlayer (ETL) has garnered considerable attention. This configuration\nleverages the high electron mobility of ZnO and the favorable surface\nstate of ZnMgO. Furthermore, the versatility of this configuration\nextends to its wide range of thickness tunability, rendering it suitable\nfor the construction of thick devices for top-emitting structures\nwith microcavities. However, despite the promising attributes of this\nbilayer configuration, the impact of the ZnO/ZnMgO bilayer ETL interface\non QD-LEDs performance remains largely unexplored. Thus, this study\ninvestigated the effect of ultraviolet ozone (UVO) treatment on the\nstabilization of the ZnO/ZnMgO interface. UVO treatment was found\nto significantly enhance luminance uniformity across the QD-LEDs emission\narea while improving operational stability by over 4-fold. Comprehensive\nanalyses employing X-ray photoelectron spectroscopy and Fourier-transform\ninfrared spectroscopy confirmed that UVO treatment significantly reduced\nthe defect states of the hydroxyl groups and removed the insulating\nnative ethanolamine ligands, thereby facilitating improved and uniform\nelectron transport. Moreover, the effectiveness of UVO treatment in\nenhancing electron transport was supported by impedance analyses.\nTherefore, this paper presents an effective approach for enhancing\nthe interface of a highly potent ZnO/ZnMgO bilayer ETL, which can\nultimately improve the luminance uniformity and stability of QD-LEDs.