助熔剂对Eu~(2+)掺杂的碱土金属硅酸盐荧光粉发光性能的影响

研究了不同助熔剂对Eu2+掺杂的MgO·2SrO·SiO2发光性能的影响。结果表明:加入3%(质量分数)BaF2作为助熔剂时样品发光效果最好。对400nm紫外光激发下样品的发射光谱进行了Gauss拟合,出现了3个发光中心。采用van Uitert提出的Eu2+5d激发态带边位置与配位数的经验公式进行计算,认为3个发光中心是由Eu2+分别取代Sr(Ⅰ)格位、Sr(Ⅰ)格位附近形成的杂质束缚激子态和Sr(Ⅱ)格位形成的。晶体场强度与X—O键长成反比,随着掺入助熔剂阳离子半径的增大,发射光谱发生了红移。

EFFECTS OF DIFFERENT FLUXING AGENTS ON THE LUMINESCENT PROPERTIES OF Eu~(2+)-DOPED ALKALINE EARTH SILICATE PHOSPHORS

Effects of different fluxing agents on the luminescent properties of Eu~(2+)-doped MgO·2SrO·SiO_2 phosphors were studied. The results indicate that the sample with 3% in mass BaF_2 as fluxing agent has the best luminescence property. The emission spectrum excited by 400 nm ultraviolet light was evaluated by Gaussian fitting. There are three luminescent centers in the spectrum. According to the calculated result with the empirical formula proposed by van Uitert, the three luminescent centers can be originated from the substitution of Eu~(2+) ions for Sr (Ⅰ) lattice sites, the impurity-bound exiton states near the Sr (Ⅰ) sites and Sr (Ⅱ) sites, respectively. Since the crystal-field strength is inversely proportional to the bond length of X-O bond, the emission spectrum shows a red-shift with the increase of radius of fluxing agent cation.