Strong circularly polarized photoluminescence from mixed halide perovskite nanocrystals induced by anion-assisted chirality imprinting

Active optical materials with intrinsic chirality, in particular, circularly polarized luminescence (CPL), are highly demanded for utilization in data processing, bioimaging, and photocatalytic asymmetric synthesis. Crystal structure engineering, chiral assembly, and chirality imprinting by chiral ligands were proposed for fabrication of CPL-active materials. The former approach is applicable to colloidal perovskite nanocrystals (PNCs), which attract significant attention due to their outstanding optical properties and high tunability. However, the issues of chiral perovskite NC stability, control of the bandgap, and achieving high photoluminescence quantum yield and emission dissymmetry factor simultaneously remain unresolved. To overcome these obstacles, we developed mixed-halide chiral perovskite NCs by simultaneous anion and ligand exchanges, which provide the passivation of surface defects and induce a chiral response. As a result, the chiral PNCs exhibit CPL with dissymmetry factors up to 3.4 × 10⁻² and a photoluminescence quantum yield up to 98 %, making the proposed approach promising for chirality imprinting. © 2024 Elsevier B.V.