Fluorescent nanocomposites based on gold nanoclusters for metal ion detection and white light emitting diodes

Abstract

Gold nanoclusters (AuNCs) are among the most promising organic–inorganic hybrid luminescent materials for various applications. The current development of AuNCs majorly focuses on controlling their luminescence properties. Herein, we report a new strategy to facilely construct two different nanocomposites featuring enhanced photoluminescence based on mercaptopropionic acid-protected AuNCs (MPA-AuNCs). Through co-assembly with Zn²⁺ and 2-methylimidazole (2M-IM), the weak luminescence of MPA-AuNCs evolved into either intense blue-green or orange emission at different concentration ratios of additives. HR-TEM and spectroscopic characterization studies revealed that the intense blue-green emission was ascribed to the formation of ZnS quantum dots (QDs) on the outer surface of AuNCs (AuNCs@ZnS), while the strong orange emission originated from the primitive MPA-AuNC core encapsulated by a cubic ZIF-8 shell (AuNCs@ZIF-8). The AuNCs@ZnS nanocomposite was further applied as an exceptional chemical sensor for selective detection of Pb²⁺ and Fe³⁺via different quenching mechanisms, and the AuNCs@ZIF-8 composite was applied for fabricating light-converting devices. The co-assembly of AuNCs with Zn²⁺ and imidazole derivatives provides a facile strategy for acquiring differentiated nanomaterials that have versatile potential applications in chemical detection and light-converting devices.