Solvent-Driven Surface-State Reconstruction of ZnMgO for Stable Blue QLEDs
Jing Zhou1, Xuejiao Zhou2, Noor Zaman1,3
1Chinese Academy of Sciences CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Guangzhou510640, China.
Abstract:
Blue QLEDs face a critical challenge in balancing high luminous efficiency with operational stability, primarily due to uncontrolled electron injection and interfacial trap-assisted recombination. Here, we present a facile aqueous ZnCl2 post-treatment strategy to engineer ZnMgO (ZMO) electron transport layers (ETLs). This approach leverages a synergistic mechanism of hydrolysis-induced recrystallization and chloride-mediated surface passivation to transform defective nanocrystal films into high-quality transport layers. The treated ETLs exhibit a reconstructed crystalline morphology with reduced grain boundary density and passivated oxygen vacancies. Consequently, without any pre-aging treatment, the optimized blue QLEDs exhibited a threefold increase in both external quantum efficiency (EQE, 5.47%) and operational lifetime (T50, 5.2 × 103 h), along with a twofold enhancement in luminance (2.4x104 cd/m2), compared to the control devices. This work demonstrates a facile method to manipulate the surface and bulk properties of metal oxide ETLs, effectively mitigating efficiency roll-off and providing a strategy for commercial high-brightness display technologies.
