Detecting Methylphenethylamine Vapor Using Fluorescence Aggregate Concentration Quenching Materials

Organic thin-film fluorescent sensors for vapor with high sensitivity, rapid response, and no pollution to analytes have received widespread attention. However, the development of vapor sensors is very slow. The difficulty lies in most fluorescent materials cannot luminesce in solid state because of ACQ (aggregate concentration quenching) effect. Previous works have usually focused on the design and synthesis of new materials to avoid ACQ effect. Whereas, if existing ACQ materials can be utilized, it will greatly expand the selection range of fluorescent materials used in vapor sensors. In this study, a high-performance vapor sensor utilizing ACQ fluorescent material was successfully prepared based on doping/breath figure method. Firstly, the fluorescence emission of ACQ molecule in solid state was realized by doping with polymer. Then porous sensing film was fabricated via breath figure method (BFs) with large surface-to-volume ratio. Finally, the vapor sensing of ACQ molecule was realized. Herein, the molecule BOR-CHO was selected as ACQ probe doping with polystyrene to get good solid-state luminescence. Then high-quality porous sensing film was obtained by optimizing the BFs parameters. Such a film showed a quick fluorescence quenching response to MPEA (simulant of methamphetamine) gas within 20 s with a detection limit of 1.58 ppm. Our results identify a simple strategy to get enhanced optical intensity of BOR-CHO and achieve superior sensing performance towards MPEA. Most importantly, these findings provide a low-cost method for the facile realization of high surface-to-volume ratio fluorescent sensors for vapor analytes via using ACQ materials, with great flexibility and expandability.