Perovskite Light‐Emitting Diodes Achieved by PVK Embellish ZnO Electron‐Transporting Layers

Currently, in metal halide perovskite light‐emitting devices, the interface between functional layers is crucial as it determines the injection and distribution of charge carriers. Herein, by inserting a poly[9‐vinylcarbazole] (PVK) layer between the sol–gel ZnO and perovskite layers, excessive electron injection is blocked, thereby improving the distribution of charge carriers in the device. Additionally, the trap density in the perovskite film is reduced. The performance of the device is enhanced, achieving a maximum current efficiency of 17.5 cd A −1 , which represents a significant 30% improvement compared to devices without the PVK layer. This new understanding offers important implications for the operational mechanism of quantum light‐emitting diode.