High-performance pure blue-emitting CsPbBr₃ nanoplatelets via amino acid-mediated strategy

CsPbBr₃ nanoplatelets (NPLs) have gained significant attention as promising blue-emitting materials due to their large exciton binding energy and narrow full width at half-maximum (FWHM) of emission spectra. However, the weak binding ability of ligands to the surface of pure blue-emitting CsPbBr₃ NPLs results in reduced optical properties and stability. Here, a ligand passivation strategy was developed for synthesizing monodisperse pure blue-emitting CsPbBr₃ NPLs with enhanced photoluminescence (PL) by incorporating phenylalanine (PHE) ligands during NPLs growth. Due to the simultaneous interaction of the amino and carboxyl groups of PHE with the lead halide octahedron formed, the growth of CsPbBr₃ NPLs in the vertical direction is inhibited, while the surface defects of the NPLs prepared are effectively passivated. As a result, combined with the post-treatment with oleamine bromide (OAmBr), the synthesized monodisperse CsPbBr₃ NPLs show an emission peak centered at 461 nm with a narrow FWHM of 16 nm and a PLQY value of 98%.