Bi ₂ X ₃ (X=O and S) Quantum Dots: Preparations and their Fluorescence Properties for Facile Detection of Ferric Ion

Water‐soluble Bi ₂ O ₃ and Bi ₂ S ₃ quantum dots (QDs) are successfully synthesized using a novel, simple, and environmentally friendly one‐pot method. X‐ray diffraction and transmission electron microscopy analyses indicate that both Bi ₂ O ₃ and Bi ₂ S ₃ QDs are well‐crystallized, with average diameter of 1.84 ± 0.02 and 2.96 ± 0.05 nm, respectively. The prepared QDs exhibit excellent fluorescence properties that remain stable over the long term. Notably, their fluorescence can be selectively quenched by Fe ³⁺ with remarkable anti‐interference capability. Furthermore, the fluorescence intensity demonstrates a strong linear correlation with the concentration of ferric ions across a wide range, facilitating effective detection of Fe ³⁺ . The mechanism underlying the fluorescence quenching by Fe ³⁺ is primarily attributed to the overlap between the absorption spectrum of Fe ³⁺ and either the excitation light or emission spectrum of Bi ₂ O ₃ and Bi ₂ S ₃ QDs. In addition, when compared to atomic absorption spectrophotometry and ultraviolet spectrophotometry for detecting Fe ³⁺ , the fluorescence method utilizing these prepared QDs offers enhanced operational efficiency and user‐friendliness. This study not only broadens the application scope of bismuth oxide and bismuth sulfide in environmental monitoring but also provides significant insights for synthesizing water‐soluble bismuth‐based QDs.