稀土掺杂双钙钛矿结构红色荧光粉的制备及其发光性能

采用高温固相反应法制备了Sr_(2-x)BaxMgMoO_6∶Eu~(3+)(x=0~1)双钙钛矿结构红色荧光粉。探讨了预处理及煅烧制度、Ba取代量对Sr_(2-x)BaxMgMoO_6∶Eu~(3+)荧光粉的相结构和发光性能的影响。Sr_2Mg_(0.94)Eu_(0.06)MoO_6荧光粉最佳制备工艺为:在700℃下预处理1h再升温至1050℃预处理1h并随炉降温后研细,再在1300℃煅烧4h,所得样品主相为双钙钛矿结构的Sr2MgMoO6四方相。其最强发光峰位于617nm附近,对应于Eu3+的5D0→7F2电偶极跃迁。随着Ba2+对Sr2+的取代量的增加晶体对称性提高,晶体结构由四方相变为立方相,样品的激发峰强度显著提高。由于晶体对称性的提高,抑制了荧光粉在617nm处5D0→7F2红光发射,其发光由电偶极跃迁占主导转变为磁偶极跃迁占主导。

Preparation and Luminescence of Rare-earth Doped Double Perovskite Red Phosphors

Double perovskite red phosphors Sr2 － xBaxMgMoO6∶Eu3+(x＝0,0.5,1,1.5,2) were synthesized by the high temperature solid-state reaction method . In present work , effects of calcination condition and Ba substitution content on the phase structure and luminescence properties of Sr2 － xBaxMgMoO6∶Eu3+(x＝0,0.5,1,1.5,2) phosphors were studied .The optimum calcination process of Sr2Mg0.94Eu0.06MoO6 phosphors was :700℃ for 1 hour ,1050℃ for 1 hour and then 1300℃ for 4 hours ,and the obtained sample had a tetragonal double perovskite main phase with a small amount of SrMoO 4and Sr3MoO6. The phosphors showed a strong wide charge transfer band between 300 nm to 450 nm ,and a high red emission of Eu3+under 399 nm excitation ,which was correspondent to the 5D0→ 7F2electrical dipole transition of Eu3+.With the increase of Ba substitution content for Sr ,the luminescent emission of the samples was significantly improved while the crystal structure changed from tetragonal system to cubic one .Because the 5D0→ 7F2electrical dipole transition of Eu3+was depressed due to the improvement of crystal symmetry ,the luminescent emission was dominated from electrical dipole transition to magnetic one .