Ultra-bright pure green perovskite light-emitting diodes

Inorganic perovskites, such as CsPbX 3 (X = Cl, Br, I), have attracted attention due to their excellent thermal stabilities and high photoluminescence quantum efficiencies. Here, we report on all-inorganic light-emitting diodes (LEDs), including inorganic perovskite emitters (CsPbBr 3 ) based on the heterostructure of n-ZnO/Al 2 O 3 /CsPbBr 3 /p-GaN. The effects of the CsPbBr 3 and Al 2 O 3 interlayers on the electroluminescence performance have been systematically investigated. It is observed that the Al 2 O 3 interlayer plays an important role in determining the emission performance. By introducing the Al 2 O 3 layers, the electron–hole recombination can almost be limited within the perovskite. The emission peaks of the heterojunction LEDs change from blue-green to pure green with the increased luminous intensities and decreased leakage currents. It provides an idea for the preparation of all-inorganic perovskite LEDs.