掺杂锶对莫来石光谱特性的影响

Photoluminescence characteristics of the mullite doped with strontium

采用高温固相法合成了Eu激活的掺杂锶的莫来石发光材料。通过XRD分析合成后样品的组成。利用荧光分光光度计测量激发光谱和发射光谱并分析发光机理。结果表明,纯莫来石的激发光谱为位于300nm的单峰,对应Eu3+的7F0-5 H3跃迁,而掺杂锶后所得激发光谱主峰分别位于260和328nm,为典型的宽波段双峰结构,分别来自于Eu2+的4f7(8S)→4f65d1(t2g)和4f7(8S)→4f65d1(eg)跃迁。机理分析表明,掺杂Sr形成的SrAl2Si2O8中,Sr2+占据Al 3+位置后导致出现负电空位,经基质作用传递给Eu3+,使Eu3+还原为Eu2+,使体系出现Eu2+的特征发光。

Europium activated luminescent mullite doped with strontium were synthesized by solid-state reaction. The synthesized product was characterized by XRD method to determine the phase compositions. The spectrophotometer was used to analyze the excitation and emission spectra and luminescence mechanisms were discussed. The results indicate that the excitation spectrum of pure mullite was a single peak at 300nm, ascribed to Eu3＋ ions transition from 7F0 to 5H3. However the excitation spectrum of mullite doped strontium is the typical broad bands with two peaks at 260 and 328nm, which caused by 4f7（8S）→4f65d1（t2g） and 4f7（8S）→4f65d1（eg） of Eu2＋ ions respectively. The best concentration of activator in the system is 3%. Luminescent mechanism reveals that the substitution of Sr2＋ for Al3＋ induced the negative vacancy to be appeared in SrAl2Si2O8, which attributed mainly to Eu3＋ to be reduced to Eu2＋ through matrix transport, and lead to the characteristic emission of the Eu2＋. The peak of emission spectrum is at 410nm, showing bright blue color.