Orange-luminescent CeO2:Sm3+ phosphor thin films were fabricated on quartz glass substrates by a sol-gel method with a spincoating technique. The films obtained were first treated with an aqueous L(+)-ascorbic acid solution as a reductant at room temperature, resulting in a considerable decrease in their photoluminescence (PL) intensity. The films with the quenched PL were then treated with an aqueous H2O2 solution as an oxidant also at room temperature, which could recover PL to more than its initial intensity of the as-prepared films. It was experimentally demonstrated that such a luminescence switching behavior in CeO2:Sm3+ was predominantly caused by redox reactions between the films and the redox species in the solutions based on a change in the Ce4+/Ce 3+ valance state of a CeO2 host crystal. A rapid response and a repetitive responsivity were then achieved with the CeO 2:Sm3+ thin films against the redox solutions, realizing a facile monitoring of redox states by the luminescence switching phenomenon.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials