Fluorine-doped carbon nitride quantum dots: Ethylene glycol-assisted synthesis, fluorescent properties, and their application for bacterial imaging

Fluorine-doped carbon nitride (F C 3 N 4 ) quantum dots were successfully synthesized on a large scale by a facile ethylene glycol-assisted ultrasonic method using bulk F C 3 N 4 powder as the precursor and ethylene glycol as the solvent. Characterization results show that high-quality F C 3 N 4 quantum dots with a uniform size of 1.5–2.0 nm were successfully prepared in ethylene glycol. Ethylene glycol is found to play an important role in the synthesis of quantum dots. Doping of fluorine in C 3 N 4 could adjust the band gap structure of C 3 N 4 , resulting in altering the emission peak position and increasing the fluorescent intensity. The as-prepared F C 3 N 4 quantum dots in ethylene glycol show much higher fluorescent intensity with the quantum yield of 39.03%. The prepared F C 3 N 4 quantum dots were successfully applied as a fluorescent probe for bacterial imaging.