Fig. 1. Molecular structures of different types of two-dimensional perovskites

Fig. 2. Crystal morphology of (PEA)₂PbBr₂Cl₂ and (C₆H₁₈N₂O₂)PbBr₄

Fig. 3. XRD pattern of the two-dimensional perovskite

Fig. 4. Schematic diagram of self-trapping exciton（STEs）and optical characterization of(PEA)₂PbBr_xCl_4−x

Fig. 5. Fluorescence spectra, excitation spectra, absorption spectra and chrominance diagrams of (PEA)₂PbBr₂Cl₂ and (C₆H₁₈N₂O₂)PbBr₄

Fig. 6. Fluorescence lifetime of(PEA)₂PbBr₂Cl₂ and (C₆H₁₈N₂O₂)PbBr₄

Fig. 7. EL spectra and CIE coordinates of LED under different voltages