Synthesis of Vitamin B1-Stabilized Gold Nanoclusters with High Quantum Yields for Application as Sensors

Gold nanoclusters (AuNCs) have received extensive attention due to their outstanding biocompatibility and excellent optical and electrochemical properties. However, the disadvantages of lower quantum yield (QY, usually <10%) and time-consuming synthetic processes severely limit their wide applications. Herein, a rapid and convenient synthetic strategy for AuNCs with higher QY is developed. AuNCs with excellent photo-/thermal stability can be one-pot-synthesized in several minutes only using vitamin B1 (VB1) as both the stabilizer and reducing agent at room temperature, which can be used for the large-scale synthesis of AuNCs. More interesting is that the QY of AuNCs@VB1 can be easily modulated by pyridine (Py) and greatly enhanced to 66.27% (AuNCs@VB1/Py). To our knowledge, this is the first report on the synthesis of AuNCs with higher QY in several minutes using VB1 as a protective agent. The QY enhancement mechanism of AuNCs@VB1/Py is also investigated in detail, and it is proven that the electron injection from Py to AuNCs accelerates the irradiative transition and thus increases its fluorescent emission. Furthermore, fluorescence sensing for glutathione (GSH) and hypochlorite detection has been successfully constructed based on the suppressed fluorescence of AuNCs@VB1/Py by GSH and then restored by hypochlorite. In brief, this work offers a convenient strategy for rapid and large-scale synthesis of AuNCs with higher QY, which will have a wide range of applications in the fields of biolabeling, sensing, bioimaging, and so on.