Surface Passivation Engineering for Stable Optoelectronic Devices via Hydroxyl-Free ZnMgO Nanoparticles

ZnMgO nanoparticles (ZMO NPs) are widely used as electron transport layers in optoelectronic devices such as light-emitting diodes (LEDs) and photodiodes (PDs) owing to their facile synthesis and excellent electron transport properties. However, the surface hydroxyl groups (‒OH) on ZMO NPs introduce charge traps, inhibit electron transport, and reduce device stability, particularly under ambient humidity and oxygen. An alcohol treatment (AT) method was developed in this study to remove surface ‒OH via proton transfer, effectively reducing trap states and dipole moments and enhancing surface passivation. Quantum-dot-based LEDs and PDs fabricated using the AT-based ZMO NPs exhibited remarkably improved current density, luminance, and external quantum efficiency in relation to the untreated devices. Notably, methanol-treated devices achieved an operational lifetime of approximately 28 h under ambient conditions, representing a substantial advancement in device stability and performance. The AT approach offers a simple and effective strategy for optimizing ZMO NPs for next-generation optoelectronic applications.