【摘要】 制备并研究了一系列具有白色长余辉的钙镁硅酸盐材料,CaxMgSi2O5+x∶Dy3+(x=1,2,3)。在紫外激发的发射谱中观察到来自Dy3+的4f组态内发射:对应4F9/2→6H15/2跃迁的蓝色发射(480nm)以及对应4F9/2→6H13/2跃迁的黄色发射(575nm)。低压汞灯(254nm)辐照后产生的长余辉光谱成分与发射谱相同,蓝光与黄光的混合组成白色光。对所研究的大部分样品,白色长余辉发射持续时间超过1h。研究了发射光强度对Dy3+浓度的依赖以及黄光与蓝光强度比与Dy3+掺杂浓度之间的关系,发现不同的基质有不同Dy3+浓度的依赖关系。室温以上的热释光谱表明所研究材料在室温以上具有丰富的热释光峰,因此有潜力进一步改善其长余辉性能。结合实验结果和以往研究,简要讨论了这一类材料的陷阱来源和长余辉发射机理。更多还原

【Abstract】 As a new generation of long afterglow phosphors, rare earth doped alkaline earth silicates and aluminates are drawing more and more attention. However, though the blue and the green phosphors with excellent afterglow performance are put into commercial use, the white afterglow phosphor suitable for illuminating is dissatisfying. Recently, a novel method of achieving stable white afterglow through combination of different coloured emissions from single activator, such as Dy3+ or Tb3+, was developed.Following this new method, a series of Dy3+-doped calcium magnesium silicate phosphors: CaMgSi2O6∶Dy3+, Ca2MgSi2O7∶Dy3+, and Ca3MgSi2O8∶Dy3+ with white long-lasting afterglow were prepared and investigated. The characteristic intra-configurational 4f emissions of Dy3+ were observed in the emission spectra as well as the afterglow spectra under ultraviolet excitation. The combination of the 480 nm blue emission corresponding to the 4F9/2→6H15/2 transition and the 575 nm yellow emission corresponding to the 4F9/2→6H13/2 transition yielded white-light emission. The white-coloured afterglow emission can last more than 1 hour for the most of the samples under study. The concentration dependence of the ratio of the yellow emission intensity to blue emission intensity was also examined and found to be varied for the different host. The thermoluminescence spectra above room temperature are employed for the discussion of the origin of the traps and the mechanism of the persistent luminescence. The calcium magnesium silicate hosts doped with Dy3+ are promi-sing candidates for the development of the white long afterglow materials, although the refinements of the materials and further investigation are needed.更多还原