Nanofibers generated from linear carbazole-based organogelators for the detection of explosives

Two linear carbazole-based conjugated compounds TC3T and PC3P with terminal triphenylamine and phenothiazine have been synthesized and showed selective gelation behaviors in some organic solvents upon ultrasound stimulation. SEM and TEM images of the xerogels revealed that 3D networks consisting of numerous nanofibers were formed in the gels of TC3T and PC3P. It should be noted that the obtained xerogels based on TC3T and PC3P emit strong blue and bluish green light, respectively, under UV irradiation. Upon exposure to the vapors of TNT and DNT, the emission of TC3T and PC3P in nanofiber-based films can be quenched obviously. The steady-state Stern-Volmer plots reveal that the fluorescence quenching of carbazole derivatives induced by aromatic nitro compounds is due to photoinduced electron transfer. Therefore, the emitting nanofibers obtained from the organogelation of linear carbazoles with terminal donors can be used as fluorescent sensors to detect explosives.