Fabrication and optical properties of MgAl₂O₄:Mn²⁺

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 ²⁺ 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 Mn ²⁺ introduction. The defects compete with Mn ²⁺ for excitation absorption and also re-absorb luminescence of Mn ²⁺ . 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.