Supramolecular self-assembly carbazolyl radicals nanospheres triggered by ultraviolet light for explosives sensing.

In this work, we designed and synthesized a carbazole-type molecule that can form carbazolyl radicals in chloroform solution under the irradiation of UV light. The process is accompanied by an obvious change in the emission color from blue to bright green. The radicals and the neutral molecules assemble together and form nanospheres through synergistic effect of π-π stacking, intermolecular hydrogen bonds and charge transfer interaction. High resolution-transmission electron microscopy (HR-TEM) is used to confirm the nanospheres. The radius sizes of the nanospheres are mainly in 80-100nm. Further, these nanospheres act as the fluorescence sensor for explosives detection, and they exhibit high selectivity and sensitivity to 2, 4, 6-trinitrophenol (TNP). The limit of detection for nanospheres is 1.2×10(-7)M.