Fig. 1. Crystal structure of Na₂Zn₃Si₂O₈ in different directions

Fig. 2. XRD patterns of the Na₂Zn₃Si₂O₈：3%Er³⁺，1%Mg²⁺ and rietveld refinement of Na₂Zn₃Si₂O₈：3%Er³⁺，1%Mg²⁺

Fig. 3. Emission spectra and concentration burst mechanism of Na₂Zn₃Si₂O₈：3%Er³⁺ and Na₂Zn₃Si₂O₈：3%Er³⁺，1%Mg²⁺

Fig. 4. Fourier transform infrared spectroscopy （FT-IR）picture of Na₂Zn₃Si₂O₈：3%Er³⁺，1%Mg²⁺ phosphor

Fig. 5. Variable temperature emission spectra of Na₂Zn₃Si₂O₈：3%Er³⁺，1%Mg²⁺ at 980 nm excitation and variation of normalized emission peak integrated intensity vs peak intensity

Fig. 6. Effect of temperature on the monochromaticity of Na₂Zn₃Si₂O₈：3% Er³⁺，1% Mg²⁺ phosphors under 980 nm excitation and CIE coordinates