Strongly blue-luminescent N-doped carbogenic dots as a tracer metal sensing probe in aqueous medium and its potential activity towards in situ Ag-nanoparticle synthesis

•Highly luminescent water soluble carbon dots to sense metals was prepared.•Carbon dots can sense metals in ppm level i.e. 'tracer sensing'.•The N-doped carbon dots (NCDs) have very much stable in its strong fluorescence property.

Milligram scale one-pot synthesis of N-doped, blue luminescent, highly water soluble and short fluorescent lifetime carbogenic dots have been developed by thermal coupling of tris(hydroxymethyl)aminomethane (tris) and glycine. The size distribution is in the range of 1.5-4.5 nm with a high abundance of 3 nm particles. The atomic force microscopy (AFM) also confirms the TEM particle size data. The carbogenic dots show pH sensitive and excellent saline environment stability without diminishing major fluorescent character. The nitrogen doped carbon dots (NCDs) can anchor Cu2+ ions in aqueous solution which results major drop off effect in fluorescence intensity by inner filter effect. Our as prepared CDs have a unique ability to detect Cu2+ ion with a detection limit of 0.32 μM in the dynamic range of 0.4-300 μM. The prepared carbon dots have also showed potential activity as a reducing agent. Here, silver nanoparticles have been synthesized without using any external rigorous reducing agent or conditions. Meanwhile our synthesis was also less time consuming and the derived carbon dots can also stabilize the nanoparticles without agglomeration up to several weeks.

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