MgAl2O4:Mg荧光粉的合成及其发光性能

用超声辅助聚丙烯酰胺凝胶法合成了MgAl₂O₄:Mg荧光粉。在MgAl₂O₄体系中引入的Mg金属颗粒抑制了MgAl₂O₄相的形成，在900℃及以上的温度烧结MgAl₂O₄:Mg干凝胶粉末，镁颗粒氧化成MgO。Mg金属颗粒的引入使MgAl₂O₄:Mg荧光粉的形貌由细小的纳米颗粒变为方便面型；MgAl₂O₄:Mg荧光粉的颜色由在600℃烧结时的暗棕色变为在800℃烧结时的白色，在1000℃烧结时白色变暗。随着烧结温度的提高MgAl₂O₄:Mg荧光粉的能带先增大后略微减小。引入镁颗粒使荧光光谱中位于395和425 nm的两个荧光峰淬灭，在650、656和680 nm出现三个新的荧光发射峰，且随着烧结温度的提高发光强度减弱。金属颗粒的表面等离子体共振导致MgAl₂O₄主晶格荧光淬灭，缺陷能级使MgAl₂O₄:Mg荧光粉产生了新的荧光发射峰。

Fabrication and Photoluminescence Properties of MgAl2O4: Mg Phosphors

A novel MgAl₂O₄:Mg phosphor was prepared by ultrasonic assisted polyacrylamide gel method. When Mg metal particles were introduced into the MgAl₂O₄ system, the formation of MgAl₂O₄ phase was inhibited. When the xerogel powder MgAl₂O₄:Mg was sintered at 900℃ or above, the incorporated Mg-particles are oxidized to be MgO. The introduction of Mg-particles greatly changed the morphology of MgAl₂O₄:Mg phosphors, namely from tiny nanoparticles to instant noodles-like. The results show that the sintering temperature has great influence on the color, light absorption capacity, energy band E_g and photoluminescence properties of MgAl₂O₄:Mg phosphors. The color of MgAl₂O₄:Mg phosphors changes from dark brown for sintering at 600℃ to bright white at 800℃ and then to light white at 1000℃. With the increase of sintering temperature the E_g value of MgAl₂O₄:Mg phosphors increased first and then decreased slightly. The photoluminescence spectra show that three new photoluminescence emission peaks located at 650, 656 and 680 nm are observed when the excitation wavelength is 325 nm. The photoluminescence intensity decreased with the increasing of sintering temperature. The fluorescence emission peaks at 395 and 425 nm of host lattice MgAl₂O₄ were quenched. The surface plasmon resonance (SPR) of Mg metal particles led to the fluorescence quenching of MgAl₂O₄ host lattice, and the defect energy level can produce a new fluorescence emission band at 635~690 nm of MgAl₂O₄:Mg phosphors.