Reduced carbon dots employed for synthesizing metal nanoclusters and nanoparticles

Carbon dots (CDs) have been considered as ideal and promising fluorescent materials owing to their excellent optical, electronic and biocompatible properties including photoluminescence, photostability, electron transfer behavior and biocompatibility. Interestingly, reduced state carbon dots (r-CDs) have emerged as a new type of CDs. Herein, we successfully prepared CDs based on cysteine serving as the carbon source, and further creatively synthesized r-CDs via simply introducing NaBH4 into the solution of CDs. Significantly, this type of r-CDs innovatively played the role of a reducer for directly synthesizing AuNCs and AuNPs (AgNPs), the reductive groups on their surfaces providing r-CDs with excellent electron-donating capability, thereby facilitating the fast reduction of metal ions to corresponding metal nanoclusters or nanoparticles. Besides, this exploration may open a new scope of CD applications in synthesis of metal nanomaterials.