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.