Due to the dual role as an electron acceptor and an electron donor in solution, carbon dots (Cdots) have broad applications in environmental analysis, biological detection, and biosensors. Herein, we report a facile-green strategy for a large-scale synthesis of fluorescent N, P-doped
carbon dots (N, P-Cdots) with an absolute quantum yield of 66.08% by a simple one-step thermal decomposition. Glucose was selected as a carbon precursor and tryptophan (Trp) as an N-doping and passivation reagent. Organic polar solvents with a high boiling point, i.e., ethylene glycol and
glycerol, were used as the reaction medium, and phosphoric acid was employed as a P source and oxidation accelerator. It is shown that the emission wavelength of the N, P-Cdots can be tuned by adjusting the reaction conditions, such as mass ratio, heating time, temperature, and medium, without
further passivation. Finally, advantage was taken of the superior fluorescent characteristics of N, P-Cdots to detect selectively and with high sensitivity a cancer marker, carcinoembryonic antigen (CEA), based on the fluorescent quenching mechanism. Additionally, CEA was also detected in
human serum samples with high efficiency and RSD, further confirming that the proposed method has a good consistency and stability for supersensitive fluorimetric detection of cancer markers.
Dual roles of a transparent polymer film containing dispersed N-doped carbon dots: A high-efficiency blue light converter and UV screen