The construction of Tb3+ doped Sr–BDC metal–organic framework materials and their high-sensitivity fluorescent detection of Fe3+

Abstract

This study presents the synthesis of a strontium-based metal–organic framework (Sr–BDC) through a solvothermal method, employing strontium chloride and terephthalic acid as primary precursors. The as-prepared Sr–BDC was subsequently functionalized with terbium ions (Tb³⁺) to yield a Tb³⁺@Sr–BDC composite. Extensive structural characterization, including X-ray diffraction (XRD), thermogravimetric analysis (TG), and the scanning electron microscope (SEM), confirmed that the Tb³⁺ incorporation preserved the integrity of the Sr-MOF framework without inducing structural degradation. Photoluminescence analysis demonstrated that Tb³⁺@Sr–BDC exhibits distinct Tb³⁺ emission peaks at 545 nm upon excitation at 294 nm, showcasing exceptional selectivity and sensitivity toward Fe³⁺ ions. Stern–Volmer quenching analysis revealed a remarkably low detection limit of 7.3 × 10⁻⁶ mol L⁻¹ for Fe³⁺, with a linear response range spanning from 5 × 10⁻⁶ to 1 × 10⁻⁴ mol L⁻¹. The potential mechanisms responsible for Fe³⁺-induced fluorescence quenching in Tb³⁺@Sr–BDC was also analysised in the study. These results underscore the potential of Tb³⁺@Sr–BDC as a highly efficient fluorescent probe for applications in environmental monitoring and biomedical sensing.