Perovskite quantum dots as a fluorescent probe for metal ion detection in aqueous solution via phase transfer

Abstract Perovskite quantum dots (QDs) have the sensing applications only in organic solution because of their instability in water. In this communication, we report an ingenious way to detect Cu2+ in aqueous solution based on the CsPbBr3 (CPB) QDs. The idea is that adding strong organic ligand (oleylamine, OAm) to selectively transfer Cu2+ ions from water to cyclohexane to quench fluorescence of CPB QDs. Due to the strong interaction between the amine ligands and the metal ions, OAm in cyclohexane can capture Cu2+ from water to form OAm-Cu2+ complexes at the interface of cyclohexane/water. These Cu2+ complexes can rapidly diffuse into cyclohexane and finally quench PL of the CPB QDs. The linear range, high selectivity, response time and quenching mechanism of the probe were studied.