Eu³⁺ -Eu²⁺ -doped xAl₂ O₃ -ySiO₂ and xAl₂ O₃ -zMgO composites phosphors

In this paper, the Eu³⁺ -Eu²⁺ (4%, molar ratio)-doped xAl₂ O₃ -ySiO₂ (x = 0-2.5, y = 1-5) and xAl₂ O₃ -zMgO (x = 0-1.5, z = 0-3) composites phosphors with different Al₂ O₃ to SiO₂ (A/S) and Al₂ O₃ to MgO (A/M) ratios were prepared using a high-temperature solid-state reaction under air atmosphere. The effects of the A/S and A/M on luminescence properties, crystal structure, electron spin resonance, and Commission Internationale de l'Eclairage chromaticity coordinates of the samples were systematically analyzed. These results indicated that the different A/S and A/M ratios in the matrix effectively affected the crystal phase, degrees of self-reduction of Eu³⁺ , and led the relative emission intensity of Eu²⁺ /Eu³⁺ to change and adjust.