MgAl2O4: xMn2+ phosphors with various Mn2+ mole fraction x has been synthesized by high temperature solid-state reaction method. Upon blue excitation at 450 nm, the green emission band at 520 nm of Mn reaches the maximal intensity at x = 10%. Our study indicates that there is no considerable concentration quenching for x higher than 10% . The decrease of luminescence for x > 10% is due to more defects generated by Mn2+ introduction. The defects compete with Mn2+ for excitation absorption and also re-absorb luminescence of Mn2+. The temperature induced luminescence enhancement has been observed. The result is well explained in connect with the defects acting as traps basing on diffuse reflection spectra at different temperatures.
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