CuAl2O4和CuAl2O4：Cr荧光粉的合成及发光机理研究

采用温和的溶胶-凝胶法以酒石酸作为螯合剂制备了铝酸铜（CuAl₂O₄）和CuAl₂O₄：Cr荧光粉。X射线粉末衍射结果表明,铝酸铜干凝胶在800 ℃烧结获得了纯的立方相的铝酸铜,而CuAl₂O₄：Cr干凝胶烧结后为铝酸铜和三氧化二铬的混合相。元素组分与电荷态分析表明,铝酸铜和CuAl₂O₄：Cr荧光粉中不含其他杂质元素,且存在少量的吸附氧。扫描电镜分析表明,铝酸铜和CuAl₂O₄：Cr荧光粉的颗粒形状近似呈球形,每个大的颗粒由很多细小的晶粒组成,CuAl₂O₄：Cr荧光粉颗粒间的团聚现象较为明显。光学性质分析发现,CuAl₂O₄：Cr荧光粉颗粒间明显的团聚现象导致它的光学带隙值比铝酸铜小。采用255 nm的光激发CuAl₂O₄：Cr荧光粉,在690 nm处获得了一个强的荧光发射峰,主要归因于Cr³⁺中²E_g→⁴A_2g的跃迁。

Study on synthesis and photoluminescence mechanism of CuAl2O4and CuAl2O4:Cr phosphors

CuAl₂O₄ and CuAl₂O₄：Cr phosphors were prepared by a mild sol-gel method with tartaric acid as chelating agent.The X-ray powder diffraction results showed that the CuAl₂O₄ xerogel sintered at 800 ℃ exhibited a pure cubic CuAl₂O₄ phase with high crystallinity,CuAl₂O₄：Cr phosphor after sintering of xerogels was a mixed phase of CuAl₂O₄ and Cr₂O₃.The analysis of elemental composition and charge state showed that the CuAl₂O₄ and CuAl₂O₄：Cr phosphors did not contain other impurity elements,and there was a small amount of adsorbed oxygen in the two samples.Scanning electron microscope analysis showed that the particles of CuAl₂O₄ and CuAl₂O₄：Cr phosphors were approximately spherical,and each large particle was composed of many fine grains.The agglomeration phenomenon among CuAl₂O₄：Cr phosphor particles was obvious than that of CuAl₂O₄.The optical properties analysis found that the agglomeration of CuAl₂O₄：Cr phosphor particles resulted in a smaller optical band gap than that of CuAl₂O₄.CuAl₂O₄：Cr phosphor stimulated at 255 nm,and a strong fluorescence emission peak was obtained at 690 nm,which was mainly attributed to the transition between²E_g and⁴A_2g in Cr³⁺.