Ordered chiral liquid-crystal corona on CsPbBr3 nanoplatelets enables bright and strong circularly polarized luminescence

Chiroptical perovskite emitters are promising circularly polarized light sources, but it remains difficult to simultaneously realize high photoluminescence efficiency and strong CPL in structurally uniform nanocrystals. Here we report a surface-engineering strategy that integrates emitter shape anisotropy with liquid-crystal (LC) ligand engineering. Quasi-isotropic CsPbBr3 quantum dots are transformed into anisotropic quasi-2D CsPbBr3 nanoplatelets (PNs), followed by coordination of cholesterol-based chiral LC ligands to construct chiral perovskite nanoplatelets with surface-bound LC ligands. This design preserves high brightness while markedly boosting chiroptical activity, delivering a PLQY up to 91% with dissymmetry factors up to gabs = 1.4 × 10−2 and glum = 8.4 × 10−3. Beyond the nanoscale, these chiral PNs efficiently transfer chirality to an achiral nematic LC host (5CB), inducing macroscopic helical superstructures. Finally, polarization-gated multilevel anti-counterfeiting patterns and QR-code encryption are demonstrated as a proof-of-concept application of the chiral PNs–LC hybrids.