Centrifugal-Coated Quasi-Two-Dimensional Perovskite CsPb₂Br₅ Films for Efficient and Stable Light-Emitting Diodes

The optical, structural, and electroluminescent (EL) characteristics of pure quasi-2D CsPb₂Br₅ were reported. We fabricated continuous, compact, well-crystallized CsPb₂Br₅ films by centrifugal coating from a colloidal solution containing CsPb₂Br₅ nanoparticles. The centrifugal-coated CsPb₂Br₅ films have a photoluminescence quantum yield (PLQY) of ∼35% because of its low-dimensional structure. Taking advantage of the high PLQY, we fabricated perovskite light-emitting diodes (PeLEDs) with a centrifugal-coated CsPb₂Br₅ emitting layer exhibiting bright green EL, a maximum luminance of 7317 cd m^-2, an and external quantum efficiency of 1.1%. Additionally, the EL color could be changed easily from green to red using a halogen exchange method. The half lifetime of our CsPb₂Br₅ PeLEDs reached around 6 h under continuous operation at 10 mA cm^-2.