采用高温固相法合成出系列绿色Ca5-xEux(SiO4)2F2荧光粉, 并对其发光特性进行了研究。Eu2+离子在Ca5(SiO4)2F2基质中可被250~440 nm光有效激发发出绿光, 适合作为 UV-LED用绿色荧光粉。浓度猝灭实验结果表明, Eu2+离子的最佳掺杂摩尔分数为0.15, 通过计算推测出Eu2+离子在Ca5-xEux(SiO4)2F2中的能量转移机制应该为偶极-偶极相互作用。温度猝灭特性表明, 450 K时的发射强度约为10 K时的35%。不同温度下Eu2+离子的荧光寿命结果表明, 随着温度的不断升高, 荧光寿命不断缩短。

A series of new green-emitting phosphors, Eu2+-activated Ca5-xEux(SiO4)2F2 were synthesized at 1 223 K by conventional high-temperature solid-state reactions under reductive atmosphere. And the photoluminescence excitation, diffuse reflectance and emission spectra, concentration quenching process, temperature dependence of luminescence and lifetime of phosphors were systematically investigated. The excitation spectrum shows that Ca5(SiO4)2F2∶Eu2+ can be efficiently excited by the incident lights of 250～440 nm, perfectly matching with the emissions wavelength of near-UV LEDs. The emission intensity is influenced by the Eu2+ content, and the optimal doping mole fraction is about 0.15. The concentration quenching mechanism was verified as dipole-dipole interaction and the value of the critical transfer distance was calculated as 1.5 nm. The temperature dependent emission spectra in the temperature range of 10~450 K show that the emission intensity at 450 K is 35% of the emission intensity at 10 K. At room temperature, the lifetimes of Eu2+ ions in Ca4.85Eu0.15(SiO4)2F2 phosphors are determined to be 1.78 μs and 7.79 μs, respectively. All of these indicate that Ca5(SiO4)2F2∶Eu2+ is a promising green phosphor candidate for phosphor-converted white LEDs.