Enhanced Stability and Performance in Perovskite Nanocrystal Light‐Emitting Devices Using a ZnMgO Interfacial Layer

Abstract Perovskite has been considered to be a promising optoelectronic material due to its superior properties, yet, it are strongly sensitive to oxygen and water, especially when applied in devices. Here, a highly efficient and stable light‐emitting device (LED) is reported by applying solution‐processed Mg‐doped ZnO (MZO) nanocrystals (NCs) as an interfacial layer. The effect of Mg doping on the optical and electronic properties of NCs is investigated. This study demonstrates that the air stability of perovskite NC film is significantly enhanced because of the decreased oxygen vacancy surface sites of MZO NCs. Incorporation of a MZO layer with favorable electronic energy level to form a suitable band alignment promotes electron injection and enhances the LED performance. Compared to the device without MZO, the LED shows 3059 cd m⁻² of luminance, with 1.9 times enhanced current efficiency and 2 times increased external quantum efficiency. In addition, the device with MZO also exhibits better stability. This research provides a potential strategy for realizing stable and efficient perovskite LEDs.