Taurine-grafted carbon dots for chemical sensing

Although the synthesis of carbon dots by bottom-up approach is extensively reported, a greener synthetic method and facile separation of the product are essential requirements. Herein, we report a one-step hydrothermal method for the large-scale fabrication of a blue fluorescent N, S-doped carbon dot (NSCD) by using citric acid and 2-aminoethanesulfonic acid as precursors. This NSCD can reversibly respond to the change in temperature in water and in polyvinyl alcohol (PVA) film within the temperature range of 10 °C to 90 °C with sensitivity 1.92%/°C and 0.36%/°C respectively. Further, these NSCD can be spread over a cellulose paper to develop a strip-based sensor to detect trinitrophenol (TNP) with an LOD of 0.14 nM, which is the lowest among the reported visual detection techniques for TNP. In addition, the intense emissive nature NSCD/PVP (polyvinylpyrrolidone) composite makes it a valuable material for imaging latent fingerprints on several substrates such as aluminum foil, glass slide, plastic, and ceramic tiles under visible light and fluorescent microscope.