Red phosphorescence properties of Mn ions in MgO–GeO2 compounds

Abstract
Red phosphorescence properties on Mn ions doped MgO–GeO2 compounds, Mg4GeO6, Mg2GeO4, and MgGeO3, were investigated. The red phosphorescence was observed in MgGeO3:Mn2+. The red phosphorescence intensity of MgGeO3:Mn2+ increased with adding the MgF2 and Yb2O3. The red phosphorescence duration time of sample with a batch composition of 44 mol%-MgO, 6 mol%-MgF2, 50 mol%-GeO2, 0.1 mol%-MnO, and 0.05 mol%-Yb2O3 is approximately 30 min. The mechanism of red phosphorescence in MgGeO3:Mn2+ is discussed in terms of the relationship between valency state of manganese ions and point defects in matrix compound.