A novel thermally-activated delayed fluorescent probe based on hydroxyl as identify group for detection of iron ions

•The hydroxy group can detect Fe3+specifically as identity group.•TADF structure can enhance the fluorescence lifetime of the probe.•The probe has a fast response time and the detection can be completed within 1 s. A thermally-activated delayed fluorescent (TADF) probe TPA-SOOH was designed and synthesized for the detection of iron ions, which based on triphenylamine sulfoxide as luminescence nucleus and the hydroxyl as identification group. Low temperature phosphorescence spectroscopy indicated that the probe possesses a small singlet and triplet splitting (ΔEST) of 0.16 eV, which ensured the reverse intersystem crossing (RISC) for TADF process. Thermogravimetric test results demonstrated that the probe has good thermal stability with glass transition temperature above 70 °C. Fluorescence testing revealed that the probe is obvious characteristics of iron ion response and the limit of detection is 13 nM obtained by titration experiment. Moreover, the probe had good fluorescence stability in different acid-base environments, which benefited for its practical application. This study firstly proved that TADF material can be used as fluorescence probe for ion detection, which would further expand the material system of fluorescent probe. [Display omitted] .