新型黄绿色发光材料Sr_2MgSi_3O_9:Ce^(3+),Tb^(3+)的合成及光谱分析

Synthesis and spectral analysis of novel yellowish-green emitting phosphors Sr_2MgSi_3O_9:Tb^(3+),Ce^(3+)

采用凝胶-燃烧法在活性炭弱还原气氛下成功合成了新型荧光粉Sr2MgSi3O9:Tb3+、Sr2MgSi3O9:Ce3+,Tb3+,用X射线粉末衍射仪(XRD)、扫描电镜(SEM)、荧光分光光度计等对合成产物进行了分析和表征。结果表明,所合成的发光材料与Sr2MgSi2O7具有相似的晶体结构,同属四方晶系。样品一次颗粒近似球形,粒径在100nm左右。Sr2MgSi3O9:Tb3+的激发光谱为一位于249nm的宽带,发射光谱主要由473、491、547、585nm等一系列发射峰组成,其中473nm(5D3→7F3)为主发射峰,547nm(5D4→7F5)为次发射峰;样品Sr1.955MgSi3O9:Tb30.+04,Ce03.+005的激发光谱由峰值分别位于249和335nm的双激发带组成,其中后者为主激发带。在335nm激发下,其发射光谱由两部分组成,其中400nm附近的带状发射对应于Ce3+的发射,而491、547、588nm处的发射峰归属为Tb3+的5D4→7FJ(J=6,5,4)跃迁发射,最强峰位于547nm,对应Tb3+的5D4→7F5跃迁。此外,探讨了Ce3+掺杂量对样品发光亮度的影响,发现Ce3+可以把能量传递给Tb3+,对Tb3+起到敏化作用。

Novel phosphors Sr2MgSi3O9 ： Tb^3＋ and Sr2MgSi3O9： Tb^3＋ , Ce^3＋ were synthesized by gel-combustion method in weak reductive environment. The as-synthesized phosphors were investigated by XRD,SEM and fluorescence spectrophotometer. The results show that Sr2MgSi3O9 ： Tb^3＋ and SrzMgSi3O9 ：Tb^3＋,Ce^3＋ phosphors possess the similar tetragonal crystal structure as that of Sr2MgSi2O7. The initial particles of as-synthesized phosphors are nearly spherical in shape, and the particle size is about 100nm in diameter. The excitation spectrum of Sr2MgSi3O9 ： Tb^3＋ is a broad band and the main peak is at 249nm. The emission spectrum is composed of a series of peaks, located respectively at 473,491,547 and 585nm. The main peak is at 473nm （^5D3→^7F3）,and the secondary peak is at 547nm（^5D4→^7F5）. The excitation spectrum of Sr1.955MgSi3O9： Tb0.01^3＋ , Ce0.005^3＋ displays two broad bands with two peaks around 249 and 335nm respectively; the latter peak is much stronger than the former. Under 335nm irradiation,the emission spectrum is composed of two parts. One part is a broad band at around 400nm, which belongs to the emission of Ce^3＋. The other part is composed of a series of peaks,located respectively at 491,547 and 588nm. These emission peaks are ascribed respectively to Tb^3＋ ions transition of ^5D4→^7FJ （J = 6,5,4） in Sr2MgSi3O9 ： Tb^3＋, Ce^3＋. The main emission peak is at 547nm（^5D4→^7F5）. Moreover,the effect of Ce^3＋ doping amount on luminescent intensity was discussed. It is found that energy transfer from Ce^3＋ to Tb^3＋ is efficient and sensitization lie in Ce^3＋ to Tb^3＋ in Sr2MgSi3O9 host under UV light.