Green Synthesis and Characterization of High-Performance Europium Complex/CaCO₃ Core-Shell Fluorescent Materials

In this study, Eu (III) complex/CaCO₃ composite fluorescent materials were prepared by employing CaCO₃ as a substitute for conventional alkaline reagents. The composite materials were comprehensively characterized by means of FT-IR, XRD, TG-DTA, SEM, TEM, ICP, EDS, and fluorescence spectroscopy to investigate their structural and performance properties. The results demonstrated that a CaCO₃-core@shell structure was successfully constructed in the composite material. Through this structural configuration, the acid present in the reaction system was effectively neutralized by CaCO₃, while an environmentally benign preparation process was simultaneously achieved. The fluorescent properties of the composite material were systematically investigated. A maximum absolute quantum yield of 48.39% was measured, representing a 3.39% enhancement compared with the pristine Eu (TTA)₃Phen complex. Concurrently, the fluorescence lifetime in the composite material was stable at 0.78-0.80 ms due to reduced quenching from the dilution effect of CaCO₃. Furthermore, when the composite material was implemented in LED devices, warm-tone red emission was achieved with a fluorescent intensity of 21,970 cd/m² being attained. A novel strategy for preparing green and resource-efficient rare earth complexes was developed in this study. The composite material was demonstrated to possess potential applications in agricultural films, lighting, and display technologies.