Effect of Er3+-Yb3+ additions on the crystallization and luminescence properties of ZnO-WO3-B2O3-SiO2 glass ceramics

Er3+ doped and Er3+-Yb3+ co-doped ZnO-WO3-B2O3-SiO2 glass-ceramics have been prepared by melt-crystallization method and their properties are examined by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffractometry (XRD) and fluorescence spectroscopy. The results reveal that Er3+ ions or Er3+-Yb3+ ions have already entered into the crystalline field. The up-conversion mechanism of Er3+-Yb3+ co-doped ZnO-WO3-B2O3-SiO2 glass ceramics is analyzed, and the effect of Yb3+ concentration on the intensity of up-conversion is investigated. With the increase of pump power, the intensity of green emission at 530 nm increases faster than that at 552 nm. The fluorescence spectrum reaches a maximum when the molar ratio of Er2O3 to Yb2O3 is 1:7.