Up-conversion color tunable and red luminescence of Ho3+/Yb3+ co-doped glass ceramics containing NaLaSiO4 crystals

Abstract

By using the melt-annealing method, silicate precursor glasses were prepared. Optimal heat treatment conditions for glass ceramics at 610 °C for 90 min were established through a series of tests. Glass ceramics containing NaLaSiO4 crystals with β-K2SO4 structure were successfully synthesized after heat treatment. XRD patterns of glass ceramics were successfully fitted using Rietveld refinement, with rare earth ions entering the lattice by replacing sites of La resulting in a reduction in cell volume. A tunable emission from green light to red light was achieved by varying the Yb3+ doping concentration. By varying the concentration of Ho3+, the intensity of the up-conversion emission was significantly increased while maintaining high color purity in red light. The optimal concentration of Ho3+ was 0.4%, when the red light color purity was 98.9%. These results indicate that glass ceramics containing NaLaSiO4 crystals co-doped with Ho3+-Yb3+ could be used for up-conversion color-tunable emission and red luminescence.