One-Step Hydrothermal Synthesis of Highly Fluorescent MoS[sub.2] Quantum Dots for Lead Ion Detection in Aqueous Solutions

Lead ions in water are harmful to human health and ecosystems because of their high toxicity and nondegradability. It is important to explore effective fluorescence probes for Pb[sup.2+] detection. In this work, surface-functionalized molybdenum disulfide quantum dots (MoS[sub.2] QDs) were prepared using a hydrothermal method, and ammonium tetrathiomolybdate and glutathione were used as precursors. The photoluminescence quantum yield of MoS[sub.2] QDs can be improved to 20.4%, which is higher than that for MoS[sub.2] QDs reported in current research. The as-prepared MoS[sub.2] QDs demonstrate high selectivity and sensitivity for Pb[sup.2+] ions, and the limit of detection is 0.056 μM. The photoluminescence decay dynamics for MoS[sub.2] QDs in the presence of Pb[sup.2+] ions in different concentrations indicate that the fluorescence quenching originated from nonradiative electron transfer from excited MoS[sub.2] QDs to the Pb[sup.2+] ion. The prepared MoS[sub.2] QDs have great prospect and are expected to become a good method for lead ion detection.