N,S-Co-Doped Carbon Dots as Fluorescent Probes with Dual Functionality for the Detection of Picric Acid and Antibacterial Properties

Carbon dots co-doped with nitrogen and sulfur (N,S-CDs) are produced from polyethyleneimine (PEI) and thiourea through a simple one-pot hydrothermal technique. The N,S-CDs demonstrate a significant luminescent emission, achieving a fluorescence quantum yield of 60.88%.The addition of picric acid result in a reduction of the emission. The quenching mechanism is attributed to the inner filter effect. The linear detection range for picric acid is 0–300 μmol/L, with a detection limitation of 28 nmol/L. N,S-CDs also display strong antibacterial activity and low toxicity.This work demonstrates that N,S-CDs possess substantial value in the detection of picric acid as well as in the advancement of antibacterial materials.