Efficient and stable InP quantum-dot light-emitting diodes formed by premixing 2-hydroxyethyl methacrylate into ZnMgO

Abstract

Quantum dot light-emitting diodes (QLEDs) are intensively developed in the display industry owing to their outstanding optoelectronic properties. However, their limited stability significantly limits broader display applications. Recently, a few studies have highlighted a phenomenon known as positive aging, in which post-treatment with a UV-curable acidic resin enhances both the lifetime and efficiency of QLEDs, thus offering a promising approach for overcoming limited lifetimes. Nonetheless, these treatments involve high-viscosity acidic resins, necessitating simpler processes for practical commercialization. In this study, a comparable performance-enhancing effect was verified by simply premixing the most abundant component of acidic resin, 2-hydroxyethyl methacrylate (HEMA), with ZnMgO (ZMO) to create an electron transporting layer. The QLED developed in this study, which incorporates HEMA-premixed ZMO, demonstrated 1.4- and 2.1-fold improvements in external quantum efficiency and half-lifetime, respectively. Comprehensive analyses of both the thin films and devices were conducted to elucidate the reasons behind these enhancements. To achieve a simplified method instead of resin-induced post-treatment, 2-hydroxyethyl methacrylate, a component of the resin, was pre-mixed with ZnMgO nanoparticles, leading to enhanced efficiency and lifetime.