The effects of cooling rate on the structure and luminescent properties of undoped and doped SrAl2O4 phosphors

Undoped and doped SrAl2O4 were synthesized by the Proteic sol-gel method using different cooling rates. The structural properties were investigated using X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM). The concentration of monoclinic and hexagonal phases in each sample calcined at the same temperature but with different cooling rates was determined via XRD Rietveld refinement. The effect of different cooling rates on the radioluminescence (RL) properties of undoped and doped SrAl2O4 phosphor also was investigated and the results suggest that the Eu3+ → Eu2+ reduction process depend on the relative concentration of monoclinic and hexagonal phases in the sample.