Aqueous synthesis of functionalized copper sulfide quantum dots as near-infrared luminescent probes for detection of Hg²⁺, Ag⁺ and Au³.

ABSTRACT: Stable water-soluble copper sulfide(Cu₂S) quantum dots(QDs) with near-infrared emission were synthesized using N-acetyl-L-cysteine(NAC) as a modifier in aqueous solution and nitrogen atmosphere at room temperature. The product was characterized by TEM, XRD, XPS, FT-IR, FL and UV-VIS spectrometers. Effects of preparation conditions such as pH values, the molar ratio of reactants, temperature, and metal ions on the fluorescence properties of Cu₂S QDs were discussed. Under optimal conditions, the prepared Cu₂S QDs with average diameter about 2-5?nm show a near-infrared emission at 770?nm with the excitation wavelength of 466?nm, and have a good detection sensitivity for ions of Hg²⁺, Ag⁺ and Au³⁺, based on the characteristic of fluorescence quenching. The fluorescence quenching mechanism was proposed via electron transfer with cation exchange, which based on the theory of Hard-Soft-Acid-Base (HSAB) and Ksp value of metal-sulfide.

SUBMITTER: Du W 

PROVIDER: S-EPMC5597581 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature