【摘要】 采用高温固相法合成了一系列M_xCa_2-xSiO₄:0.5mol%Ce³⁺,4mol%Al³⁺（M=Mg,Sr,Ba;x=0.05,0.1,0.15,0.2）荧光粉,通过X射线衍射仪、扫描电镜、荧光光谱仪对荧光粉的结构、形貌和光学性能进行了表征。结果表明,Mg²⁺掺杂量在x=0.05时合成的荧光粉物相与未掺Mg²⁺时一致,为γ-Ca₂SiO₄;在450nm激发下特征峰位于565nm,主要源于Ce³⁺的5d→²F_7/2和5d→²F_5/2跃迁;Mg²⁺掺杂量在x=0.1⁰.2时,荧光粉物相变为β-Ca₂SiO₄,并随着Mg²⁺的浓度增大,出现杂相,在365nm激发下发射峰位置由503nm迁移至423nm。Sr²⁺掺杂量在x=0.05⁰.15时,合成的荧光粉物相为γ-Ca₂SiO₄,激发和发射光谱与未掺Sr²⁺时基本一致;当x=0.2时,物相转变为α’_H-Ca₂SiO₄荧光粉,在365nm激发下特征峰位于465nm。Ba²⁺掺杂量在x=0.05⁰.10时,荧光粉物相未有明显变化,但x=0.15⁰.20时,合成的荧光粉物相转变为α-Ca₂SiO₄,在365nm激发下特征峰位于460nm。不同离子掺杂获得的荧光粉物相及发光性质变化的原因实际是,由于参与反应的碱土氧化熔点逐渐降低,Mg²⁺、Sr²⁺和Ba²⁺进入Ca₂SiO₄晶格引起相变的趋势在增强。更多还原

【Abstract】 A series of M_xCa_2-xSiO₄:0.5mol%Ce³⁺,4.0 mol%Al³⁺（ M=Mg,Sr,Ba; x= 0.05,0.1,0.15,0.2） phosphors was prepared by high temperature solid-state reaction. The structure,morphology and luminescent properties of the phosphors were studied by X-ray diffractometer,scanning electron microscope and fluorescence spectrometer. The results show that the structure of γ-Ca₂SiO₄phase maintains when x = 0.05 for Mg_xCa_2-xSiO₄: Ce³⁺,Al³⁺phosphor. Under the excitation of 450 nm light,a broad band emission centered at 565 nm is observed,which mainly corresponds to the 5d→²F_7/2 and 5d→²F_5/2 transitions of Ce³⁺. When x grows up to 0.1 0.2,the phase is changed to β-Ca₂SiO₄ with impurity phase. With the increase of the doping concentration,the emission peak of Mg_xCa_2-xSiO₄:Ce³⁺,Al³⁺ shifts from 503 nm to 423 nm under the excitation of 365 nm. When x = 0.05 0.15 for Sr_xCa_2-xSiO₄: Ce³⁺,Al³⁺phosphor,the structure and luminescent properties are almost same as those of the Sr-free phosphor. When x = 0.2,the phase is changed to α’_H. Under the excitation of 365 nm,the emission peak locates at 465 nm. When x = 0.05 0.10 for Ba_xCa_2-xSiO₄: Ce³⁺,Al³⁺phosphor,the structure and optical properties are almost unchanged,however,the phase transforms to α-Ca₂SiO₄ when x = 0.15 0.2. The emission peak locates at 460 nm under the excitation of 365 nm. The reason for phase transformation and the change of luminescence properties of these phosphors are owing to the difference of melting points of alkali-earth metal oxides. The trend of phase transformation from γ- Ca₂SiO₄ to other phases is enhanced with the doping from Mg²⁺ to Sr²⁺ and Ba²⁺.更多还原