Redox luminescence switch based on Mn 2+ ‐doped NaYF 4 :Yb,Er upconversion nanorods

An redox luminescence switch was developed for the sensing of glutathione (GSH), l ‐cysteine (Cys) or l ‐ascorbic acid (AA) based on redox reaction. The Mn 2+ ‐doped NaYF 4 :Yb,Er upconversion nanorods (UCNRs) with an emission peak located in the red region were synthesized. The luminescence intensity of the UCNRs could be quenched due to the Mn 2+ could be oxidized to MnO 2 by KMnO 4 . Subsequently, when the AA, GSH or Cys was added into the MnO 2 modified upconversion nanosystem, which could reduced MnO 2 to Mn 2+ and the luminescence intensity was recovered. The concentration ranges of the nanosystem are 0.500–3.375 mM (R 2  = 0.99) for AA, 0.6250–11.88 mM (R 2  = 0.99) for GSH and 0.6250–9.375 mM (R 2  = 0.99) for Cys, respectively.