Covalent organic hollow nanospheres constructed by using AIE-active units for nitrophenol explosives detection

The development of conjugated nanomaterials with high sensitivity and super-amplified quenching effect for the detection of nitrophenol explosives is still a great challenge. Herein, we developed conjugated hollow nanospheres constructed by using aggregation-induced emission (AIE) active 1,3,5-tris(4-formyl-phenyl)benzene (TFPB). The high emission hollow nanospheres with uniform size and admirable dispersiveness exhibited obvious fluorescence quenching response with the addition of nitrophenol explosives owing to the photoinduced electron transfer (PET) from the hollow nanospheres to nitrophenol explosives. The Stern-Volmer constants of hollow spheres for 2,4,6-trinitrophenol (TNP), 4-nitrophenol (NP) and 2,4-dinitrophenol (DNP) can reach 9.67x10(5), 3.14x10(5) and 4.8x10(4) M-1, respectively. Furthermore, the handy test paper coated with hollow nanospheres was prepared and showed a good response toward TNP solutions and vapor. The study provides a novel strategy to construct AIE-active conjugated hollow nanospheres for efficient nitrophenol explosives sensing.