2-(2-Hydroxyphenyl)benzoazole-based AIEgens with interesting photoresponse property

Abstract

As a typical class of aggregation-induced emission luminogens (AIEgens), 2-(2-hydroxybenzene)benzoazole (HBZ)-based molecules are widely applied in organic light emitting diodes, white-light emitters, chemosensors and bioimaging materials. However, there are few reports on the photoresponsive properties of HBZ-based AIEgens. In this work, three HBZ-based AIEgens 2-(2-hydroxy-3-methylphenyl)benzothiazole (1), 2-(2-hydroxy-3-methylphenyl)benzoxazole (2), and 2-(2-hydroxy-3-methylphenyl)benzimidazole (3) were found to exhibit remarkable photoresponse characteristics in alkaline aqueous solutions under UV light irradiation. The important kinetic information of the photoresponse processes was obtained by time-dependent fluorescence spectra, including kinetic orders, rate constants, and apparent activation energies. The mechanism study showed that the ring-opening hydrolysis reactions of the benzoazole moieties in 1–3 were responsible for the photoresponsive properties. Based on this finding, 1–3 were successfully used for photo-printing in aqueous solutions and solid test papers. This work provides a new strategy for designing photoresponse systems and also enriches the application of HBZ-based AIEgens.