A turn-on TADF chemosensor for sulfite with a microsecond-scale luminescence lifetime

A reaction-based luminescence chemosensor was synthesized for sulfite detection based on a fluorescein derivative with thermally activated delayed fluorescence (TADF). The chemosensor exhibited a fluorescence turn-on effect on sulfite with good sensitivity and selectivity. Importantly, utilizing the long luminescence lifetime of the TADF compound, the chemosensor realized photoluminescence lifetime imaging for sulfite in living cells with the luminescence lifetime distribution mainly around 14 mu s.