Chiral Rare Earth Fluoride Nanocomposites: Achieving Multicolor CPL and High-Temperature Stability
Background: Circularly polarized luminescence (CPL) materials have great potential for application in anti-counterfeiting and information encryption due to their unique optical polarization properties. CPL materials can emit both left-handed (LCP) and right-handed (RCP) circularly polarized light, a characteristic that has made them highly sought after in high-security anti-counterfeiting applications. However, developing stable inorganic materials with multicolor CPL remains a challenge. Compared to organic CPL materials, inorganic CPL materials exhibit better stability, and their chiral properties can be precisely controlled by altering their chemical composition, size, and morphology. Currently, a feasible strategy for achieving assembly chirality is to control the attachment or growth of achiral nanoparticles on a chiral host, forming a spatially asymmetric arrangement.
Research Content Recently, the team led by Lu Shan at the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, published a paper entitled "Helically Assembled Rare Earth Fluoride Nanoparticles with Multicolor Circularly Polarized Luminescence for High-Security Anti-Counterfeiting" in the journal Aggregate. For the first time, they obtained chiral rare earth (RE) fluoride nanoparticles induced by helical silica through a simple in-situ assembly strategy. The effects of assembly ratio and morphology on the luminescence asymmetry factor (glum) were systematically studied, and a glum value of 4.7 × 10⁻³ was finally optimized. By adjusting the type and concentration of rare earth dopants (such as Ce³⁺, Tb³⁺, and Eu³⁺), these nanocomposites exhibited multicolor CPL and time-resolved photoluminescence (TRPL) properties. Notably, even after calcination at 400°C, these nanocomposites retained their CPL activity. Utilizing visible multicolor luminescence and hidden dynamic and chiral optical signals, these nanocomposites have been successfully applied to high-security anti-counterfeiting patterns and multi-level optical encryption codes.
Article Highlights
**Novel Chiral Rare Earth Fluoride Nanocomposites:** For the first time, chiral rare earth (RE) fluoride nanoparticles induced by helical silica were synthesized through a simple in-situ assembly strategy. These nanocomposites exhibit multicolor CPL and time-resolved photoluminescence (TRPL) properties.
Optimized Luminescence Asymmetry Factor (glum): By systematically studying the effects of assembly ratio and morphology on chiral luminescence, a glum value as high as 4.7 × 10⁻³ was achieved.
Excellent Thermal Stability: These nanocomposites retain CPL activity even after calcination at 400°C, demonstrating excellent thermal stability.
Multicolor CPL and TRPL Properties: By adjusting the type and concentration of rare earth dopants (such as Ce³⁺, Tb³⁺, Eu³⁺), multicolor CPL emission from green to orange was achieved.
High-Security Anti-counterfeiting Applications: Utilizing the multicolor luminescence, dynamic, and chiral optical signals of these nanocomposite materials, high-security anti-counterfeiting patterns and multi-level optical encryption codes were successfully designed.
Reference: W. Yuan, S. Lu, X. Li, et al., Helically Assembled Rare Earth Fluoride Nanoparticles with Multicolor Circularly Polarized Luminescence for High-Security Anti-Counterfeiting, Aggregate, 2025, 0:e70042.