Doping/Breath Figure Method Triggered Reversible Diethylchlorophosphate Vapor Sensing

Aggregation-caused quenching (ACQ) is the key reason why thin-film fluorescence sensing studies have lagged. A facile two-step strategy combining doping with breath figure method (BF) is capable to suppress the ACQ effect without sacrificing the sensing property of the molecule. In this work, two long-wavelength fluorescent probes, Me4BOPHY-1 and Me4BOPHY-2, were synthesized by introducing one or two diethylaminophenyl group in the α-position of Me4BOPHY. Upon addition diethylchlorophosphate (DCP) to the solution of the probes, the initial intramolecular charge transfer (ICT) process is restrained. Thus, the intense fluorescence from Me4BOPHY core was released together with a dramatical color change. As the typical ACQ probes, Me4BOPHY-1 and Me4BOPHY-2 can’t be used in vapor-detection directly due to their weak fluorescence in the solid-phase. By means of being doped with polystyrene solution and being spin-coated under the optimal relative humidity conditions, porous films for DCP vapor detection were prepared with a high detection performance of a 162-ppb low detection limit. Moreover, it is exciting that these films show two outstanding characters of anti-interference to HCl gas and reversibility, which have not been reported in previous studies. This work breaks the application boundary of ACQ materials and provides an inspiration for the development of thin-film fluorescence sensors.