文摘
The development of light emitting systems that exhibit turn-on type emission changes and ratiometric emission color changes is important for biological imaging applications. In this paper, we report that turn-on-type double emission changes and ratiometric emission color changes can be achieved simultaneously by exploiting the aggregation of V-shaped bis(thiadiazolo)quinoxaline- and bis(thiadiazole)phenanthroquinoxaline-triphenylamine donor–acceptor type dyes in aqueous media. When the water fraction of THF/water media in which the dyes were placed was increased, the initial red emission of the monomer state changed to an orange emission in the aggregated state via the quenching of near-infrared emissions. This unusual double emission change was attributed to the combined effect of aggregation and twisted intramolecular charge-transfer.