X-Type Ligands Effect on the Operational Stability of Heavy-Metal-Free Quantum Dot Light-Emitting Diodes

ZnSeTe quantum dots (QDs) offer an efficient avenue for realizing heavy-metal-free light-emitting diodes (LEDs) that meet the Rec.2100 blue standard. Synthetic core-shell engineering has enabled big advances in the external quantum efficiency (EQE) of ZnSeTe QD-LEDs. However, the mechanisms behind the degradation of the operational stability of ZnSeTe QD-LEDs remain relatively unexplored. In this study, we explore the impact of ligand density and composition on both material and device stability. We developed a solid-film ligand exchange utilizing an inorganic X-type ligand (zinc chloride), revealing that the substitution of inorganic ligands for organic counterparts significantly influences the stability of both materials and devices.