Lim Hyo-Jun, Dang Thi Huong Thao, Lee Nayoon, Jin Sunwoo, Vo Van-Khoe, Lee Joon-Hyung, Shin Won Sik, Jeong Byoung-Seong, Heo Young-Woo
School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, Republic of Korea.
KNU Advanced Material Research Institute, Kyungpook National University, Daegu 41566, Republic of Korea.
ACS Appl Mater Interfaces. 2025 Jan 8;17(1):1533-1541. doi: 10.1021/acsami.4c16075. Epub 2024 Dec 29.
The development of quantum dot light-emitting diodes (QLEDs) represents a promising advancement in next-generation display technology. However, there are challenges, especially in achieving efficient hole injection, maintaining charge balance, and replacing low-stability organic materials such as PEDOT:PSS. To address these issues, in this study, self-assembled monolayers (SAMs) were employed to modify the surface properties of NiO, a hole injection material, within the structure of ITO/HIL/TFB/QDs/ZnMgO/Al QLEDs. Specifically, using Br-2PACz-based SAMs resulted in surface defect passivation, improved hole injection, reduced exciton quenching, and enhanced electrical characteristics. Notably, QLEDs based on (NiO+Br-2PACz) demonstrated a turn-on voltage of 2.4 V, a maximum external quantum efficiency (EQE) of 8.30%, a maximum luminance of 88,831 cd/m, and a maximum current efficiency of 32.78 cd/A. Compared to NiO-based QLEDs, these results represent a reduction in turn-on voltage by approximately 1.5 V, a 1.99-fold increase in EQE, and a 3.63-fold increase in luminance, indicating significantly enhanced performance with notable improvements in turn-on voltage, EQE, and luminance. They also showed higher EQE and luminance than PEDOT:PSS-based QLEDs; this could be attributed to the downshifting of energy levels by Br-2PACz, which reduced the hole injection barrier, increased the conductivity, and improved charge balance. In particular, the reduction in exciton quenching and the increase in electrical conductivity contributed significantly to the overall performance enhancement of the (NiO+Br-2PACz)-based QLEDs. This paper proposes a simple method for inorganic hole injection layer functionalize and application.
量子点发光二极管（QLED）的发展代表了下一代显示技术中一项很有前景的进步。然而，仍存在一些挑战，尤其是在实现高效空穴注入、维持电荷平衡以及替代诸如PEDOT:PSS等低稳定性有机材料方面。为了解决这些问题，在本研究中，自组装单分子层（SAMs）被用于修饰氧化镍（一种空穴注入材料）在ITO/HIL/TFB/QDs/ZnMgO/Al QLED结构中的表面性质。具体而言，使用基于Br-2PACz的SAMs可实现表面缺陷钝化、改善空穴注入、减少激子猝灭并增强电学特性。值得注意的是，基于（NiO+Br-2PACz）的QLED的开启电压为2.4 V，最大外量子效率（EQE）为8.30%，最大亮度为88,831 cd/m，最大电流效率为32.78 cd/A。与基于氧化镍的QLED相比，这些结果表明开启电压降低了约1.5 V，EQE提高了1.99倍，亮度提高了3.63倍，这表明在开启电压、EQE和亮度方面有显著改善，性能得到了显著增强。它们还显示出比基于PEDOT:PSS的QLED更高的EQE和亮度；这可能归因于Br-2PACz使能级下移，从而降低了空穴注入势垒，提高了电导率并改善了电荷平衡。特别是，激子猝灭的减少和电导率的增加对基于（NiO+Br-2PACz）的QLED的整体性能提升有显著贡献。本文提出了一种用于无机空穴注入层功能化及应用的简单方法。
