Wang and co-workers synthesized benzoselenadiazole based diarylamine as a near-infrared optical sensor for F−, and the designed sensor showed a turn-on ratiometric fluorescence signalling with F−by inhibiting the excited state intramolecular proton transfer processes [21]. However, the sereported dyes based probes for Ca2+ and F−are faced with the poor water solubility which severely restricts their application in water environment systems. Moreover, synthesis of many organic dyes is complex and expensive.Compared with traditional organic dyes and fluorescent proteins, quantum dots (QDs), as a kind of inorganic nanomaterials,have attracted more attentions owing to their unique optical properties including size tunable fluorescence, narrow and symmetric emission peak with a broad excited wavelength, and excellent photostability,