Spectral conversion from green to red in Yb3+/Ho3+: Sr2GdF7 glass ceramics via Ce3+ doping

Ce3+ co-doped Sr2GdF7:Yb3+/Ho3+ transparent oxyfluoride glass ceramics were successfully fabricated through melt-quenching technique, which were further confirmed by intense diffraction peaks of X-ray diffraction, transmission electron microscopy, selected area electron diffraction, obvious Stark splitting of emission spectra and prolonged lifetimes of Ho3+ after crystallization. Under 980 nm excitation, green upconversion emission is dominant in Sr2GdF7:Yb3+/Ho3+ glass ceramics and is about 10,000 times stronger than that in precursor glass. Furthermore, upconversion emission tuning from green to red in Sr2GdF7:Yb3+/Ho3+ glass ceramics was obtained via codoping Ce3+ ions with different concentrations. Impressively, red to green fluorescence intensity ratio increases from 0.1 to 91, which is caused by two efficient cross-relaxation processes derived from Ho3+ and Ce3+ ions. The current study on the multicolor tuning behavior of Ce3+ doped Sr2GdF7:Yb3+/Ho3+ glass ceramics offers a potential application in color displays.