High-Performance Perovskite-Based Light-Emitting Diodes from the Conversion of Amorphous Spin-Coated Lead Bromide...

Large-grained and well-oriented methylammonium lead tribromide (MAPbBr₃) perovskite was formed from the conversion of amorphous lead bromide (PbBr₂) doped with phenethylamine (PEA). The addition of PEA ions (with an optimized molar ratio of 0.008%) to the PbBr₂ solution assisted the formation of a smooth PEA-doped PbBr₂ layer by spin-coating. Then, the PEA-doped PbBr₂ thin film would convert into large-grained and well-oriented MAPbBr₃ with the help of a solid-vapor reaction under a vaporized methylammonium bromide (MABr) and choline chloride (CC) atmosphere. Furthermore, both PEA and CC would passivate the defects of perovskite to improve the crystal quality of perovskite. By applying this perovskite layer in perovskite light-emitting diodes (PeLEDs), the maximum luminance and current efficiency of PeLEDs could reach 20,869 cd/m² and 3.99 cd/A, respectively; these values are approximately five and three times larger than those of PeLEDs without PEA. The perovskite converted from spin-coated PbBr₂ with a PEA dopant remarkably improved the luminance and current efficiency of its PeLEDs.