A fast-responsive fluorescent probe for sensitive detection of graphene oxide based on MoS2 quantum dots

Abstract

Facile preparation of water soluble and fluorescent N-doped MoS₂ quantum dots (N-MoS₂ QDs) is described herein. N was introduced to reduce defects in the MoS₂ surface. The obtained N-MoS₂ QDs exhibited excellent fluorescence characteristics with good photostability and excellent stability even in 3 M NaCl solution and when stored in a refrigerator for one year. Additionally, the fluorescent N-MoS₂ QDs were developed as a simple and practical nanosensor for the detection of GO through hydrophobic π–π interactions between N-MoS₂ QDs and GO, where the excited state electron and energy transfer may occur from N-MoS₂ QDs to GO along with fluorescence quenching of N-MoS₂ QDs. These results reveal that the limit of detection (LOD) was as low as 4 ng mL⁻¹, which was able to satisfy the needs of the determination of GO in environmental water samples. Importantly, the N-MoS₂ QDs nanosensor exhibits excellent detection selectivity against other ions or molecules in the environment. In this study, the proposed sensor was successfully used for the determination of GO content in environmental water samples.