Doping effects of Nb^(5+) on red long afterglow phosphor CaTiO_3:Pr^(3+)

A series of Nb5＋ codoped red long afterglow phosphors CaTi1-xNbxO3：Pr 0.0023＋ （0 ≤ x ≤ 0.05） is prepared by a solid state reaction method. Their photoluminescence, phosphorescence and thermoluminescence are investigated. The results indicate that codoping Nb5＋ can improve the photoluminescence and phosphorescence property of CaTiO3：Pr3＋ significantly. When 3-mol% Nb5＋ is codoped, the emission intensity of CaTiO3：Pr3＋ is enhanced twice, while the afterglow time is extended from 10 min to about 40 min. Thermoluminescence results reveal that the trapping level of CaTiO3：Pr3＋ is reduced from 0.82~eV to 0.62~eV by codoping Nb5＋. The effect of Nb5＋ doping on enhancing the photoluminescence intensity and afterglow time of CaTiO3：Pr3＋ is discussed.

锌对CaTiO_3∶Pr^(3+)发光亮度和余辉时间的影响

研究了Zn的不同掺入量、不同合成温度对CaTiO3∶Pr3+红色光致发光材料结晶、初试亮度和余辉时间的影响。用X射线衍射确定了材料的物相构成,Zn的掺入没有导致Ca2Zn4Ti15O36相的出现。发射光谱的峰值位于613nm,对应了Pr3+的1D2 3F4跃迁发射,且受Zn掺入量的影响。激发光谱呈宽带,随Zn掺入量的不同而变化明显。同时,Zn的掺入量的增加可以显著降低材料的合成温度。适量的Zn的掺入,在适当的合成温度条件下,获得了具有高的初始亮度、余辉时间达1h左右的红色长余辉材料。

CaTiO_3:Pr^(3+)红色蓄能发光材料的研究

以碳酸钙、氧化锌、二氧化钛为主要原料,以氧化镨为激活剂,以氧化铕为辅助激活剂,以碳酸钠为电荷补偿剂,以硼酸为助熔剂,采用高温固相法对红色CaTiO3:Pr3+蓄光材料进行了试制研究。试制得到荧光余辉时间达20 min左右、发光效果良好的CaTiO3:Pr3+系红色荧光材料。对合成的荧光粉末进行了XRD、激发光谱分析检测,表明合成所得荧光粉的主晶相为CaTiO3。试验结果表明,在配料组成确定后,合成温度和保温时间对发光效果的影响较大。当合成温度为1100℃,保温时间为2 h制备得到的荧光材料发光效果良好。

Ti^(4+)的掺入对Y_2O_2S:Eu^(3+),Mg^(2+),Ti^(4+)陷阱分布和余辉性能的影响

用高温固相法制备了不同Ti4+掺杂量的红色长余辉材料Y2O2S:Eu3+,Mg2+,Ti4+,其X射线衍射分析、发射光谱和激发光谱均不受Ti4+掺杂量改变的影响.测量了Ti4+掺杂量不同的样品的热释光谱,随着Ti4+掺杂量的增加,热释光的峰值强度先增强后减弱,有了很大的变化;用PeakFit软件以一般阶动力学模型对Ti与Y2O2S的物质的量比分别为0.5%,2.5%和8.0%的样品进行了热释光曲线拟合,得出了它的单峰曲线并计算了与其对应的陷阱参数.陷阱分布表明:当Ti掺杂量为2.5%时,有利于合适深度陷阱的大量形成,从而使材料的发光和余辉性能得到了很大的提高.

Effect of different dopants on the long lasting phosphorescence behavior of CaTiO_3:Pr^(3+)

In order to improve the luminescence properties of CaTiO3：Pr3＋, a series of CaTiO3：Pr3＋, such as CaTi0.97Nb0.03O3：Pr3＋, Ca0.8Zn0.2TiO3： Pr3＋, Ca0.8Zn0.2Ti0.97Nb0.03O3：Pr3＋ and B3＋-doped Ca0.8Zn0.2Ti0.97Nb0.03O3： Pr3＋ were prepared through conventional solid state reaction method. The results of the photoluminescence excitation and emission spectra showed that all the samples emitted red phosphorescence at 612 nm originating from 1D2 to 3H4 emission of Pr3＋ under the 337 nm excitation. When examined by the X-ray diffraction （XRD）, all the samples presented a predominant phase of CaTiO3 （JCPDS# 42-423） except Zn2＋-doped samples which also revealed another phase of Zn2Ti3O8 （JCPDS# 73-579）. The results of the afterglow decay curves showed that co-doping Zn2＋ ions, Nb5＋ ions or adding a small amount of B3＋ into Ca0.8Zn0.2Ti0.97Nb0.03O3：Pr3＋ were effective in improving the photoluminescence properties of CaTiO3：Pr3＋ phosphor. Thermoluminescence results showed that the trap existing in all the samples was the same as in CaTiO3：Pr3＋ and doping singly Nb5＋ or Zn2＋ hardly changed the trap depth but co-doping Nb5＋ and Zn2＋ could modify the trapping level from 0.63 to 1.26 eV distinctively. In addition, adding a certain amount of B3＋ into CTO-PZN could also deepen the trap depth.

Enhancement of luminescence and afterglow in Ca_(0.8)Zn_(0.2)TiO_3:Pr^(3+) by Nb^(5+) substitution for Ti^(4+)

Nb5＋ doped Ca0.8Zn0.2TiO3：Pr3＋ red long afterglow phosphors were synthesized by solid-state reaction methods. X-ray diffraction, photoluminescence spectroscopy and thermally stimulated spectrometry were used to investigate the effects of Nb5＋ content on the crystal characteristics and luminescent properties of Ca0.8Zn0.2Ti1-xNbxO3：Pr3＋ phosphors. The results showed that the addition of a small quantity of Nb5＋ had negligible effect on the crystal characteristics of Ca0.8Zn0.2Ti1-xNbxO3：Pr3＋, but it could change the trapping parameters （the depth of trap, frequency factors and the concentration of trapped charges at t=0） of Ca0.8Zn0.2Ti1-xNbxO3：Pr3＋ phosphors, and then led to the enhance-ment of red fluorescence and phosphorescence at 612 nm originating from 1D2→3H4 transition of Pr3＋. Both of the red fluorescence intensity and afterglow time reached the largest values in the sample of Ca0.8Zn0.2Ti1-xNbxO3：Pr3＋ with x=0.05. The afterglow time of Ca0.8Zn0.2Ti0.95Nb0.05O3：Pr3＋ phosphors lasted for over 24 min （≥1 mcd/m2） when the excited source was cut off.

红色长余辉发光材料CaTiO_3:Pr^(3+)的制备与发光性能研究

采用固相烧结法制备了红色长余辉发光材料CaTiO_3:Pr^(3+),讨论了Pr^(3+)、Zn^(2+)添加量对CaTiO_3:Pr^(3+)发光性能的影响。结果表明,随着Pr^(3+)、Zn^(2+)含量的增加,材料的余辉性能先增大后减小,当Pr^(3+)含量为0.5%,Zn^(2+)含量为20%时,材料的余辉性能达到最优。对材料热释光谱的研究表明深陷阱能级的出现是长余辉性能提高的主要原因。

Zn掺杂CaTiO_(3)∶Pr^(3+)红色长余辉发光材料的制备及发光性能

采用高温固相法制备了Zn掺杂CaTiO_(3)∶Pr^(3+)红色长余辉发光材料,测试了样品的激发光谱、发射光谱和余辉衰减曲线。研究了Zn和Pr^(3+)不同加入量对CaTiO_(3)∶Pr^(3+)发光性能的影响。结果表明,加入Zn有利于样品对紫外光的吸收利用,611 nm红光发射强度明显增强。当加入0.2 mol Zn,0.002 mol Pr^(3+)和质量分数2.5%H_(3)BO_(3)时,所得Ca_(0.8)Zn_(0.2)TiO_(3)∶Pr^(3+)红色长余辉发光材料的发光性能和余辉性能最佳,其余辉初始亮度为85 mcd/m^(2)。

锗酸镉中镨的长余辉发光特性

通过高温固相法在空气条件下制得Cd2Ge7O16∶Pr3+长余辉发光材料。测其结构为一单相。分析了Cd2Ge7O16,Cd2Ge7O16∶Pr3+的激发光谱和发射光谱,指出Cd2Ge7O16∶Pr3+的发光是Cd2Ge7O16本身和Pr3+离子发射产生,基质的发光是Cd2Ge7O16中有陷阱能级,电子从导带跃迁到陷阱能级而产生,Pr3+的发光是该离子的4f-4f跃迁产生的;并把该材料的长余辉性质归结为基质结构中有电子陷阱和空穴陷阱,电子陷阱和空穴陷阱分别能储存电子和空穴,从而产生余辉。并提出余辉机理模型。