Nitrogen-doped carbon quantum dots for fluorescence sensing, anti-counterfeiting and logic gate operations

The low quantum yields (QY) of carbon quantum dots (CQDs) not only limit their sensitivity as sensors, but also hinder their application in fluorescent anti-counterfeiting materials. To develop highly fluorescent CQDs, several factors, like a large conjugated double bond system, a rigid plane structure and electron-donating substituent group incorporation on the aromatic ring need to be considered. With this in mind, herein, highly fluorescent nitrogen-doped CQDs (N-CQDs) were successfully fabricated by a solvothermal method using ammonia, citric acid and phloroglucinol as precursors. The sensing platform based on the obtained N-CQDs was constructed to determine Fe3+ and ascorbic acid (AA) via the on-off-on fluorescence principle. The fluorescence of the N-CQDs was effectively quenched upon addition of Fe3+, and then, restored by AA. The detection limits for Fe3+ and AA were determined to be 0.28 mu M and 0.81 mu M within the respective ranges of 1-10 mu M and 30-90 mu M. It is worth noting that the proposed strategy was successfully applied to monitor AA in fruit samples with satisfactory results. In addition, we successfully applied N-CQDs to information anti-counterfeiting and molecular logic gate operations, which confirmed their great potential application prospects. Fluorescent nitrogen-doped CQDs were successfully fabricated for application in fluorescence sensing, anti-counterfeiting, and logic gate operations by a solvothermal method using ammonia, citric acid and phloroglucinol as precursors.

Automated summary

Fluorescent nitrogen-doped CQDs were successfully fabricated for application in fluorescence sensing, anti-counterfeiting, and logic gate operations by a solvothermal method using ammonia, citric acid and phloroglucinol as precursors.