A Schiff base-functionalized graphene quantum dot nanocomposite for preferable picric acid sensing

Fast and effective picric acid (PA) sensing in water and the air is urgently demanded environmental safety. Herein, a new sensor was designed and synthesized mediated by graphene quantum dots (GQDs) for explosive detection. The luminescent Schiff base-functionalized GQDs (Schiff-GQDs) was immobilized on nanocomposite through in-situ electrospun. The quantitative experiment shows that the fluorescent quantum yield of SchiffGQDs is 11.63%, four times higher than that of N-GQDs (2.71%) and seven times higher than that of dye 1 (1.51%). Luminescent Schiff-GQDs have a bigger quenching percentage, better selective detection of PA where the detection limit is 3.64 x 10-5 M. More importantly, the naked-eye detection limit of the paper-based sensor has been up to 11.45 ng/cm2. Also, theoretical calculation, and proposed mechanism, as well as the host-guest interactions have been carried out for the visual detection of PA. This study can provide a useful example of novel membrane sensors for explosives combining with the two weak luminescent systems based on the molecular design of covalent-nanocomposited emission enhancement (CNEE).

Automated summary

This study presents a new sensor design mediated by graphene quantum dots for fast and effective detection of picric acid in water and air, showing higher fluorescent quantum yield and better selective detection capability. Luminescent Schiff-GQDs exhibit significant quenching effects, lower detection limits, and the ability to detect PA with the naked eye.