Fig. 1. Structural analysis. (a) Crystal structure diagram of CGZA; (b) XRD patterns of CGZA…xMn4+,yBi3+ synthesized at different temperatures

Fig. 2. (a) Excitation and emission spectra of CGZA…0.0050Mn4+, Gaussian fitting curves and splitting peaks; (b) diffuse reflectance spectra of CGZA and CGZA…0.0050Mn4+

Fig. 3. Spectral graphs of CGZA…0.0050Mn4+ samples synthesized at different temperatures. (a) Excitation spectrum (λem=703 nm ); (b) emission spectrum (λex=351-367 nm, corresponding to 4A2g→4T1g transition); (c) emission spectrum (λex=473 nm, corresponding to 4A2g→4T2g transition)

Fig. 4. Fluorescence properties of CGZA…xMn4+ sample synthesized at 1500 ℃. (a) Excitation spectra (λem =703 nm); (b) emission spectra (λex =343-373 nm, corresponding to4A2g→4T1g transition); (c) relationship between emission intensity of 2Eg→4A2g transition and Mn4+ doping concentration; (d) CIE chromaticity diagram of CGZA…0.0050Mn4+; (e) color changes of Mn4+ doped phosphors with different concentrations under fluorescent lamp

Fig. 5. Tanable-Sugano energy level diagram of the octahedral site of Mn4+ in CGZA matrix

Fig. 6. Bi3+ doping and energy transfer analysis. (a) Excitation spectra of Ca2Gd1-yZr2Al3O12…yBi3+; (b) emission spectra of Ca2Gd1-yZr2Al3O12…yBi3+; (c) excitation spectra of Ca2Gd1-yZr1.995Al3O12…yBi3+, 0.0050Mn4+; (d) emission spectra of Ca2Gd1-yZr1.995Al3O12…yBi3+, 0.0050Mn4+; (e) energy transfer diagram of Bi3+ and Mn4+ ions; (f) luminescence decay curves of Mn4+ in the Ca2Gd1-yZr1.995Al3O12…yBi3+, 0.0050Mn4+(λex =316 nm, λem=703 nm)