Fig. 1. (a) XRD pattern of Ba0.25Na0.58Y0.06F1.59∶Er0.113+ and (b) standard XRD data of BaYF5 and Na(Y1.5Na0.5)F6

Fig. 2. SEM image of Ba0.25Na0.58Y0.06F1.59∶Er0.113+

Fig. 3. Up-conversion emission spectra of L25(54) orthogonal experiment sampls (λex=1550 nm)

Fig. 4. Up-conversion emission spectra of samples doped different concentrations (a) Y3+and (b) Ba2+ (λex=1550 nm)

Fig. 5. Up-conversion emission spectra of verification sample and sample 1 (λex=1550 nm)

Fig. 6. Up-conversion emission spectra of samples 5%Er3+2%Y3+, 5%Er3+6%Y3+ and 5%Er3+16%Y3+

Fig. 7. Red and green up-conversion emission intensities and intensity ratio of green to red IG/IR of samples 5%Er3+2%Y3+, 5%Er3+6%Y3+ and 5%Er3+16%Y3+

Fig. 8. Up-conversion emission spectra of samples 11%Er3+6%Y3+, 11%Er3+12%Y3+ and 11%Er3+20%Y3+

Fig. 9. Red and green up-conversion emission intensities and IG/IR of samples 11%Er3+6%Y3+, 11%Er3+12%Y3+ and 11%Er3+20%Y3+

Fig. 10. Schematic of energy level of Er3+ and up-conversion emission mechanism of BaxNayYzF2x+y+3z+3m∶Erm3+