材料期刊网

采用简单的水热工艺制备了六方相Na(Y1.5 Na0.5)F6∶Eu3+荧光粉.300 K温度下利用394 nm光波长激发,观察到Eu3+的5Dn(n=0,1,2)→7 FJ(J=1,2,3,4)跃迁,对应主波长590 nm,色彩饱和度约为0.97.当温度升高到420 K时,仅观察到微小的色漂移.进一步拟合Ln(I0/I-1)和10 000/T的关系曲线,确定发光的热猝灭激活能约为0.324 eV.良好的热稳定性,表明Na(Y15Na0.5)F6∶Eu3+适合于功率器件的封装.在Na(Y1.5 Na0.5)F6∶Eu3+表面包覆二氧化硅后,可观察到Eu3+增强的发光,但这种荧光增强依赖于二氧化硅壳层的厚度.利用荧光增强与荧光猝灭的竞争模型解释了上述现象.

Hexagonal Na(Y1.5 Na0.5) F6 ∶ Eu3+ phosphors are synthesized by a simple hydrothermal method.At 300 K,the phosphors produce twelve emission peaks at the range of 460 720 nm when excited by 394 nm near ultraviolet radiation,corresponding to the 5 Dn (n =0,1,2)→7 FJ (J =1,2,3,4) transitions of Eu3+ ions,respec tively.The main wavelength of emission spectra is 590 nm with color saturation of 0.97.When the temperature of sample raises to 420 K,only little color shifting can be observed.Through fitting the relational curves Ln(I0/I-1) and 10 000/T,the thermal activation energy is calculated to be 0.324 eV.Na(Y1.5Na0.5)F6 ∶ Eu3+ phosphors are suitable for the bonding of power devices due to the good thermal stability.After coating SiO2 on sur face of the particles,an enhanced luminescence is obtained.But the fluorescence enhancement strongly depends on the thickness of SiO2 shell.A model on competition between enhancement and quenching is used to explain the phenomenon.