Multi-color long-lasting phosphorescence in Mn 2+-doped ZnO–B 2O 3–SiO 2 glass–ceramics

Abstract

Multi-color LLP phenomenon was observed in Mn 2+-doped ZnO–B 2O 3–SiO 2 glass–ceramics after the irradiation of a UV lamp at room temperature. Transparent ZnO–B 2O 3–SiO 2 glass emitted reddish LLP while opaque glass–ceramics prepared by the glass sample after heat treatment emitted yellowish or greenish LLP. The change of the phosphorescence is due to the alteration of co-ordination state of Mn 2+. The phosphorescence of the samples was seen in the dark with naked eyes even 12 h after the irradiation with a UV lamp ( λ max=254 nm) for 30 min. Based on the approximative t −1 decay law of the phosphorescence, we suggest that the LLP is attributed to the thermally assisted electron–hole recombination.