Trace detection of nitro aromatic explosives by highly fluorescent g-C3N4 nanosheets.

Highly fluorescent g-C3N4 nanosheets were facilely fabricated by exfoliating bulk g-C3N4 under ultrasonic irradiation for 1 h. The atomic force microscopy (AFM) image shows that the resultant g-C3N4 nanosheets are ∼6-14 nm thick, and the suspension is stable in air for several weeks. Remarkably, the obtained nanosheets exhibited strong fluorescence with an extremely high quantum yield (QY) up to 32%, and high sensitivity, selectivity, as well as a fast response to nitro aromatic explosives were observed. Typically, the quenching efficiency coefficient Ksv for PNP was 30,460 M(-1), which proved that the resultant nanosheets possessed an extremely high sensitivity for nitro-phenol PNP detection.