Helically Assembled Rare Earth Fluoride Nanoparticles with Multicolor Circularly Polarized Luminescence for High‐Security Anti‐Counterfeiting

ABSTRACT Multicolor circularly polarized luminescence (CPL) materials show considerable potential in the field of advanced anti‐counterfeiting. However, it remains challenging to achieve stable inorganic materials with multicolor CPL. In this work, for the first time, chiroptical rare earth (RE) fluoride nanoparticles induced by helical silica are obtained through a facile in situ assembly strategy. The influence of assembly ratio and morphological structure on the luminescence dissymmetry factor (g lum ) has been systematically investigated, leading to an optimized g lum value of 4.7 × 10 −3 . By adjusting the types and concentrations of RE dopants (Ce 3+ , Tb 3+ , Eu 3+ ), the nanocomposites exhibit multicolor CPL and time‐resolved photoluminescence characteristics. Remarkably, these nanocomposites retain their CPL activity even after calcination at 400°C. Leveraging the visible multicolor emissions, along with the hidden dynamic and chiroptical signals, the nanocomposites are successfully applied in high‐security anti‐counterfeiting patterns and multilevel optical encryption codes.