Room temperature driven highly crystalline fluorine-doped carbon quantum dots for sensitive tetracycline sensing

Carbon quantum dots (CQDs) with semiconductor-like properties have received considerable attention because of their unique photoelectric properties and electron transfer ability. However, the preparation of highly crystalline CQDs with strong fluorescence (FL) emission by the room temperature (RT) synthesis is a challenging task. Herein, we develop a highly-efficient RT synthesis strategy based on the Schiff base condensation reaction for preparing the fluorine-doped CQDs (F-CQDs) with good crystallinity. The as-prepared F-CQDs show strong blue FL emission with a high quantum yield of 39%, which is the highest values yet recorded for carbon dots prepared by RT synthesis. Moreover, the F-CQDs can be used for sensitive tetracycline sensing based on inner filter effect. The FL intensity ratio (F0/F) of the F-CQDs is proportional to the concentration of tetracycline in the range of 0.1–25 μM with the limit of detection of 85 nM. This sensitive assay has a good application prospect for tetracycline detection in the complex matrixes because of its simplicity and sensitivity.