Multilevel Structural Design of Chiral Lanthanide Complexes Enhancing Circularly Polarized Luminescence for Information Encryption

The concurrent enhancement of the dissymmetry factor (glum) and photoluminescence quantum yield (Φlum) remains a long-standing challenge in chiral circularly polarized luminescence (CPL) materials. Here, we propose a multilevel structural design strategy that integrates pH-regulated in situ ligand hydrolysis, mixed-ligand coordination, supramolecular self-assembly, and polymer matrix embedding to address this issue. Through the controlled hydrolysis of chiral oxazoline-based ligands, enantiomeric lanthanide complexes (R-/S-Lna and R-/S-Lnb, Ln = Eu/Tb) were obtained. The mixed-ligand system R-/S-Lnb exhibits larger glum values (0.027/–0.028 for R-/S-Eub, 0.010/–0.012 for R-/S-Tbb) and higher Φlum values ((75.2 ± 0.2)% for R-Eub and (81.5 ± 0.5)% for R-Tbb). By embedding R-/S-Lnb into PMMA matrices, we fabricate optically transparent, stable, and processable CPL-active thin films R-/S-Lnb@PMMA. The Φlum value of R-Tbb@PMMA is as high as (91.6 ± 0.6)%. Taking advantage of the dual photoluminescence and CPL features of R-/S-Lnb@PMMA films, we demonstrate their proof-of-concept applications in optical information storage and encryption.