采用高温固相反应法制备了一系列MgAl2O4∶xMn2+。在450 nm的蓝光激发下, 观察到了Mn2+的4T1→6A1跃迁的绿色发光, 发射光在x=10%时达到最大值。研究结果表明, 在x＞10%之后, 材料的发光强度没有明显减弱。发光强度的减弱是由于Mn2+导致的缺陷增多引起的。缺陷态与Mn2+对于蓝色激发光进行竞争, 并且对520 nm的发射光有再吸收过程。温度升高后的发光增强也被观察到。通过变温漫反射谱研究, 我们认为这与充当电子陷阱的缺陷态在高温下内部电子被热激发有关。

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 Mn2+ 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.