Enhanced blue emission in Er3+/Yb3+ doped glass-ceramics containing Ag nanoparticles and ZnO nanocrystals

We report the precipitation of ZnO nanocrystals, Ag-clusters, and Ag nanoparticles in Ag/Er/Yb doped borate glasses by furnace annealing and CO2 laser annealing. The XRD analysis revealed the precipitation of ZnO and Ag phases. The absorption spectra, the TEM and energy dispersive spectroscopy (EDS) revealed the incorporation of Er and Yb ions into ZnO nanocrystals formed by a laser technique and showed the surface plasmon band of Ag nanoparticles. The down-converted blue emission intensity of Er3+ ions obtained under 365 nm excitation was enhanced by more than a hundred times in the glass treated by furnace annealing, mainly due to the energy transfer from Ag-clusters. Moreover, we discussed the contribution of Ag nanoparticles and defects to emission characteristics in the glasses treated by two annealing techniques. Up-conversion emissions of the Er3+ ions under 980 nm excitation were enhanced due to the incorporation of Er3+ and Yb3+ ions into ZnO nanocrystals after thermal treatments.