Effect of Ga3+ ion doping on emission thermal stability and efficiency of MgAl2O4:Cr3+ phosphor

In this work, we fabricated a novel spinel-type phosphor material MgAl 2− x Ga x O 4 doped with Cr 3+ by the high-temperature solid-state sintering method. The crystal field environment of the spinel was tuned by replacing the Al ions with Ga 3+ ions of different concentrations. The cell volume and D q / B gradient increase from 2.82 to 2.62 with increasing Ga 3+ ion doping concentration. This also implies a gradual decrease in the field strength of the crystal. Based on this, the excitation spectra of MgAl 1.995− x Ga x O 4 :0.5%Cr 3+ phosphors yield a redshift. Increasing the Ga 3+ ion doping concentration also improves the emission intensity and thermal stability of the phosphors, and the emission intensity of the Ga 3+ -doped phosphors is significantly increased. For a Ga/Al ratio of 1, the thermal stability of the phosphor emission is optimal. The emission intensity at 140°C can maintain 76% of the emission intensity at room temperature, indicating that appropriate Ga 3+ ion doping can improve the emission efficiency and thermal stability of the phosphors.