A ratiometric fluorescent sensor for UO22+ detection based on Ag+-modified gold nanoclusters hybrid via photoinduced electron transfer (PET) mechanism

In this study, we prepared a new ratiometric fluorescent sensor by first encapsulating blue-fluorescent carbon dots (B-CDs) with SiO 2 , coupling gold nanoclusters (GSH-AuNCs) to the surface, and finally anchoring a layer of Ag + . The presence of UO 2 2+ caused fluorescence quenching of the ratiometric fluorescent probe when used in aqueous solutions. Furthermore, HOMO–LUMO orbital analysis suggested that the quenching mechanism was mainly attributed to photoinduced electron transfer (PET) between B-CDs@SiO 2 @GSH-AuNCs/Ag + and UO 2 2+ . Under optimal conditions, the ratiometric fluorescent probes exhibited excellent selectivity and detected UO 2 2+ at 37 nmol/L. This new “on–off” ratiometric fluorescent sensor exhibits promising potential for convenient monitoring of UO 2 2+ levels with ideal recovery in real-world water samples.