Soluble graphene composite with aggregation-induced emission feature: non-covalent functionalization and application in explosive detection

Herein, a soluble graphene-based material exhibiting the aggregation-induced emission (AIE) feature was prepared for the first time via wet chemistry by the chemical reduction of graphene oxide (GO). Moreover, three conjugated polymers containing tetraphenylethylene, carbazole and phenyl groups were used as stabilizers during the reduction of GO in tetrahydrofuran (THF) solution due to the π–π interaction and polymer wrapping effect; the resultant graphene composites containing different amounts of rGO were soluble in organic solvents. Among the three polymers, P1 exhibits the strongest affinity towards rGO, and rGO–P1 in THF solution is stable for months at the concentration of 1.5 mg mL−1. Furthermore, rGO–P1 is AIE-active and its PL intensity is 6.3-fold that of P1 under the same conditions (THF/H2O = 10/90, v/v). The distinguished optical properties and AIE effect of rGO–P1 allow it to act as a chemosensor for the detection of explosives in both the aggregate and solid state with high sensitivity. In the aggregate state, the detectable concentration is as low as 1.3 ppb and the quenching constant is up to 4.16 × 106 M−1, which enable its trace detection of picric acid.