MgF_(2)对Mn^(4+)掺杂锗酸盐红色荧光粉发光的影响

Effect of MgF_(2)on the luminescence of Mn^(4+)-doped germanate red phosphor

3.5MgO·0.5MgF_(2)·GeO2∶Mn^(4+)作为优异热稳定性和良好发光性能的红色荧光粉而被市场应用,然而,该粉体中MgF_(2)的作用影响机理尚不明晰,阻碍其性能进一步优化和发展。采用高温固相法制备了系列Mn^(4+)激活的锗酸盐荧光粉,通过对比加入MgF_(2)、H_(3)BO_(3)(助熔剂),研究了该粉体的结构、形貌、发光性能等变化规律,阐明了MgF_(2)的发光影响作用。研究表明,加入MgF_(2)、H_(3)BO_(3)和不加任何助熔剂时的样品,其最佳烧结温度分别为1150、1250和1350℃,上述温度下发光强度均为最佳值,其中加入MgF_(2)、H_(3)BO_(3)的样品在最佳温度处生成了纯相。MgF_(2)的添加,一方面同H_(3)BO_(3)一样作为助熔剂对生成纯相、提高样品结晶度起了积极的作用;另一方面,通过研究分析,确认F-离子成功掺杂进入晶格,促使样品生成的晶体结构为Mg_(14)Ge_(5)(O,F)_(24)。加入MgF_(2)、H_(3)BO_(3)在最佳烧结温度的样品的荧光寿命分别为0.93和0.75 ms。

3.5MgO·0.5MgF_(2)·GeO2∶Mn^(4+)has been applied in the market as a red phosphor with excellent thermal stability and good luminescence performance.However,the unclear influence mechanism of MgF_(2)in the phosphor hinders further performance optimization and development.A series of Mn^(4+)-activated germanate phosphors were prepared by the high-temperature solid-phase method.The variation regulation of the structure,morphology,and luminescence performance was investigated by comparing the addition of MgF_(2)and H_(3)BO_(3)(flux).Then the lumines-cence influence role of MgF_(2)has been obtained.The study showed that the optimum sintering temperatures for the samples with MgF_(2),H_(3)BO_(3),and without any co-solvent were 1150,1250,and 1350℃,respectively.The lumines-cence intensity at the above temperatures was also the optimum value,and the samples with MgF_(2)and H_(3)BO_(3) exhib-ited a pure phase at the temperature,respectively.The crystallinity and dispersion of the phosphors were improved by adding MgF_(2)and H_(3)BO_(3),and the positive influence of the MgF_(2)was better than that of the H_(3)BO_(3).The Dq/B value of the phosphor with MgF_(2)was calculated to be 3.03,indicating Mn^(4+)is in an environment with a strong crystal field.The fluorescence lifetimes of the phosphors with MgF_(2)and H_(3)BO_(3) were 0.93 and 0.75 ms,respectively.The addition of MgF_(2),on the one hand,plays a positive role as a co-solvent,which can be conducive to generating a pure phase and improving the crystallinity.The role is the same as the H_(3)BO_(3).On the other hand,the F-ions originating from MgF_(2)were successfully doped into the crystal lattice confirmed by the XPS analysis,and then the crystal struc-ture of Mg_(14)Ge_(5)(O,F)_(24) was achieved.