A hydrothermal route for synthesizing highly luminescent sulfur- and nitrogen-co-doped carbon dots as nanosensors for Hg2+

Abstract

Carbon dots have attracted tremendous attention due to their excellent properties, such as outstanding photoluminescence, low cytotoxicity, and superior biocompatibility. In this work, a simple and low cost method was developed to synthesize sulfur- and nitrogen-co-doped carbon dots (S/N-CDs) via hydrothermal treatment of pyritinol hydrochloride in the presence of graphene oxide (GO). The S/N-CDs displayed good water solubility, high luminescence stability, excitation-dependent emission, up-conversion photoluminescence, and strong photoluminescence with a quantum yield of ca. 32.2% without complicated surface modifications. In addition, the prepared S/N-CDs were used as a sensitive probe to detect Hg²⁺ ions, showing an excellent selectivity and wide linear range. Particularly, the detection limit could reach as low as 1.0 nM.