Lee Kyoungeun, Lee Jaeyeop, Bae Yeyun, Roh Heejae, Jung Woon Ho, Lim Jaehoon, Kim Jaehoon, Roh Jeongkyun
Department of Electrical Engineering, Pusan National University, Busan 46241, Republic of Korea.
Department of Energy Science and Center for Artificial Atoms, Sungkyunkwan University, Suwon 16419, Republic of Korea.
ACS Appl Mater Interfaces. 2024 Oct 16;16(41):55658-55665. doi: 10.1021/acsami.4c09900. Epub 2024 Oct 7.
The development of efficient charge transport layers is crucial for realizing high-performance and stable quantum dot light-emitting diodes (QD-LEDs). The use of a ZnO/ZnMgO bilayer as an electron transporting layer (ETL) has garnered considerable attention. This configuration leverages the high electron mobility of ZnO and the favorable surface state of ZnMgO. Furthermore, the versatility of this configuration extends to its wide range of thickness tunability, rendering it suitable for the construction of thick devices for top-emitting structures with microcavities. However, despite the promising attributes of this bilayer configuration, the impact of the ZnO/ZnMgO bilayer ETL interface on QD-LEDs performance remains largely unexplored. Thus, this study investigated the effect of ultraviolet ozone (UVO) treatment on the stabilization of the ZnO/ZnMgO interface. UVO treatment was found to significantly enhance luminance uniformity across the QD-LEDs emission area while improving operational stability by over 4-fold. Comprehensive analyses employing X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy confirmed that UVO treatment significantly reduced the defect states of the hydroxyl groups and removed the insulating native ethanolamine ligands, thereby facilitating improved and uniform electron transport. Moreover, the effectiveness of UVO treatment in enhancing electron transport was supported by impedance analyses. Therefore, this paper presents an effective approach for enhancing the interface of a highly potent ZnO/ZnMgO bilayer ETL, which can ultimately improve the luminance uniformity and stability of QD-LEDs.
开发高效的电荷传输层对于实现高性能和稳定的量子点发光二极管（QD-LED）至关重要。使用ZnO/ZnMgO双层作为电子传输层（ETL）已引起了广泛关注。这种结构利用了ZnO的高电子迁移率和ZnMgO良好的表面状态。此外，这种结构的通用性还体现在其广泛的厚度可调性上，使其适用于构建具有微腔的顶部发射结构的厚器件。然而，尽管这种双层结构具有诸多优点，但ZnO/ZnMgO双层ETL界面对QD-LED性能的影响在很大程度上仍未得到探索。因此，本研究调查了紫外臭氧（UVO）处理对ZnO/ZnMgO界面稳定性的影响。结果发现，UVO处理显著提高了QD-LED发光区域的亮度均匀性，同时将操作稳定性提高了4倍以上。采用X射线光电子能谱和傅里叶变换红外光谱的综合分析证实，UVO处理显著减少了羟基的缺陷态，并去除了绝缘的天然乙醇胺配体，从而促进了改善且均匀的电子传输。此外，阻抗分析也支持了UVO处理在增强电子传输方面的有效性。因此，本文提出了一种增强高效ZnO/ZnMgO双层ETL界面的有效方法，最终可提高QD-LED的亮度均匀性和稳定性。
