A ratiometric probe composed of an anionic conjugated polyelectrolyte and a cationic phosphorescent Iridium(III) complex for time-resolved detection of Hg(II) in aqueous media

A hybrid complex composed of an anionic conjugated polyelectrolyte (PFB-SO₃Na) and a cationic phosphorescent Ir(III) oligomer is formed through electrostatic interaction by simple physical mixing in aqueous media. Due to their opposite charges and their effective spectral overlap, fluorescence resonance energy transfer occurs from the blue-emissive PFB-SO₃Na to the red-emissive phosphorescent Ir(III) complex, which allows ratiometric and colorimetric Hg²⁺ sensing in aqueous solution with good selectivity, sensitivity, as well as visible detection. Time-resolved photoluminescence is applied for Hg²⁺ detection, which can effectively eliminate the background interference and improve the sensing sensitivity and signal-to-noise ratio in complicated media. An anionic conjugated polyelectrolye and a cationic phosphorescent Ir(III) complex form a hybrid probe for ratiometric Hg²⁺ sensing with good selectivity and low detection limit. Time-resolved photoluminescence is further applied to eliminate the interference from background fluorescence, which opens new opportunities for Hg²⁺ sensing in complex media.