无笼中OH-的Sm3+掺杂C12A7红光发射导电荧光粉的制备及其光学特性

Synthesis and Optical Properties of Sm3+ Doped C12A7 Red Emitting Conductive Phosphors without Encaged OH- Anions

采用碳包埋方法制备了不同Sm^3+掺杂浓度的12CaO·7Al2O3(C12A7:x%Sm^3+)导电荧光粉。样品在404 nm波长激发下,可观测到位于564,601,648,709 nm附近的4个发射峰,其分别来源于Sm^3+的4G5/2→6Hy2(J=5,7,9,11)的跃迁。当Sm^3+掺杂浓度x=0.3时,样品的光致发光强度最大。通过吸收谱结合经验公式计算可知,样品中笼中电子的浓度约为8.5×l0^19cm^-3.通过红外光谱测试可知,样品中不含困陷于笼中的0H-离子。通过在空气气氛下对C12A7:^3+导电荧光粉进行热处理,实验发现在225℃下热处理时间为50 min时,样品的阴极射线发光强度最大。通过对比含与不含笼中0H^-离子基团的优化C12A7:Sm^3+导电荧光粉的阴极射线发光特性,实验发现无笼中0H-的样品阴极射线发光强度更大,导电能力更强。实验表明:碳包埋方法制备的C12A7:Sm^3+导电荧光粉在低压电子束激发下能更好地避免电荷累积效应,在低压场发射显示领域有潜在的应用前景。

Sm^3+doped12CaO·7AL2O3(C12A7:x%Sm^3+)conductive phosphors with different concentrations were prepared by a melting solidification method.For these phosphors,four emission peaks at 564,601,648,709 nm appear upon 404 nm excitation and they originate from the 4G5/2→6Hy/2(J=5,7,9,11)transitions of Sm^3+,respectively.The strongest luminescent intensity can be observed as the Sm3+doping concentration is 0.3%.The conductive performance of these phosphors can be ascribed to the creation of encaged electrons and the calculated encaged electron concentration is?8.5x 1019 cm-3.Based on the FTIR spectra,no encaged OH-appears in C12A7:Sm^3+powders prepared by the melting solidification method.After the C12A7:0.3%Sm^3+powders were annealed at 225℃in air for 50 min,the strongest cathodoluminescence(CL)intensity can be achieved.The optimized C12A7:Sm^3+conductive phosphor without encaged OH-anions exhibits stronger CL intensity and larger conductivity compared to that with encaged OH^-anions.Our results suggest that C12A7:Sm^3+conductive phosphors prepared by the melting solidification method avoid the charge accumulation effect under low voltage electron beam excitation and they might be a potential candidate for field emission displays.