Si,Lu掺杂Ca0.8Zn0.2TiO3:Pr3+荧光粉的光学性能改善

采用高温固相法合成Ca_0.8Zn_0.2TiO₃：0.2% Pr³⁺,Si⁴⁺和Ca_0.8Zn_0.2TiO₃：0.2% Pr³⁺,Si⁴⁺,Lu³⁺荧光粉。通过X射线衍射仪、电子顺磁共振光谱仪、显微拉曼光谱仪和荧光光谱仪等表征了该系列荧光粉的物相组成、微观结构和发光性质。结果表明,以β-Si₃N₄为硅源制备的荧光粉具有最佳的光学性能。加入ZnO后,荧光粉由CaTiO₃、Zn₂TiO₄和Ca₂Zn₄Ti₁₆O₃₈三相组成,其中CaTiO₃为主相。电子顺磁共振谱证实了Pr⁴⁺存在,Lu³⁺的添加使[Pr⁴⁺Ti³⁺O₃]⁺簇显著增加,电子顺磁共振谱和拉曼光谱均证实Si⁴⁺、Lu³⁺的掺杂使局部TiO₆簇对称性提高,有利于Pr³⁺发光中心的能量传递。在336 nm激发下,荧光粉展示了很强的位于612 nm的红光发射（归属于Pr³⁺的¹D₂→³H₄跃迁）及理想的红光色坐标（x=0.670,y=0.330）。Si⁴⁺和Lu³⁺的添加显著增强了370 nm激发下红光发射,Ca_0.8Zn_0.2TiO₃：0.2% Pr³⁺,3.2% Si⁴⁺荧光粉的余辉寿命最长。     

SrB4O7：Pr3+,Mn2+中的Pr→Mn能量传递

从能量传递的角度出发,利用同步辐射光源(德国HASYLAB实验室的SUPERLUMI实验站)对Pr³⁺和Mn²⁺掺杂的SrB₄O₇粉末样品进行了光谱研究.206nm激发下,在SrB₄O₇:Pr³⁺(0.1%,摩尔分数)样品中观察到了来自Pr³⁺离子1S0能级的光子级联发射.SrB₄O₇:Pr³⁺样品的发射谱与SrB₄O₇:Mn²⁺样品监测Mn²⁺离子640nm发射的激发谱在330~430nm的波长范围里存在显著的光谱重叠.这个光谱重叠有利于Pr³⁺→Mn²⁺的能量传递发生,从而将Pr³⁺离子级联发射中第一步不实用的紫外或近紫外光子转换为Mn²⁺的红光发射.双掺杂样品SrB₄O₇:Pr³⁺,Mn²⁺与单掺杂样品SrB₄O₇:Pr³⁺的发射谱比较揭示出Pr³⁺→Mn²⁺的能量传递的确存在,并且提供了一种传递效率的估算方法,表明通过“Pr³⁺-Mn²⁺”组合有可能获得量子效率大于1的高效真空紫外激发发光材料.     

YAlO3晶体中pr3+的4f2能级

YAlO3∶pr3+是一种受到广泛关注的发光体系,本文根据文献中给出的YAlO3∶pr3+晶体中Pr3+的晶体场能级,从Nd3+离子的晶体场参数和Pr3+的准自由离子参数出发,采用f-shell计算软件包对pr3+的能级参数进行了研究,并对获得的参数进行了讨论.用拟合获得的参数计算了pr3+的4f2电子构型的所有能级.     

2018年7期 电子期刊

采用自蔓延燃烧法制备了不同镨掺杂浓度的12CaO·7Al₂O₃：Pr³⁺（C12A7：Pr³⁺） X射线影像存储荧光粉。在232 nm激发下,发现Pr³⁺掺杂摩尔分数为0.3%的荧光粉位于486 nm的蓝光发射峰呈现最大的发光强度。对C12A7：0.3% Pr³⁺样品进行真空热处理后,C12A7笼中的O^2-基团数量减少,同时类F⁺色心的空笼子的数量增多,导致陷阱数目增加和光激励发光强度增大。热释发光实验表明：C12A7：0.3% Pr³⁺样品中存在两个深陷阱,陷阱深度分别约为0.69 eV和0.80 eV;经过真空热处理后的C12A7：0.3% Pr³⁺荧光粉,陷阱深度变深,陷阱数目增多,光存储性能变好。当吸收的X射线剂量为5.2 Gy时,可以实现分辨率较高的X射线成像。实验结果表明,镨掺杂C12A7荧光粉在计算机X射线摄影领域有潜在的应用前景。     

Optical and dosimetric properties of variously doped SrF2 crystals

Optical properties and irradiation effects of Nd³⁺-, Pr³⁺-, Tb³⁺- and Tm³⁺-doped SrF₂ crystals and their possible application to solid-state dosimetry were studied and compared to those induced in pure SrF₂ crystals. Optical absorption, thermoluminescence (TL), X- and light-induced luminescence (XL and PL) as well as optically stimulated luminescence and phototransferred TL (OSL and PTTL) were measured in the various samples. Special attention was given to effects of monochromatic vacuum ultraviolet (VUV) radiation. TL was excited in the pure and doped samples by X and β rays as well as by VUV radiation. TL peaks appeared after VUV irradiation at the same temperatures and with the same thermal activation energies as after X or β irradiation, indicating that they are due to the same processes. The VUV excitation spectra showed two maxima at about 145 and 130 nm. Comparison of the TL sensitivities of the various TL materials, showed that the sensitivity of SrF₂:Pr³⁺ was by more than an order of magnitude higher than that of the known LiF:Mg,Ti (TLD-100) phosphor. The sensitivity of pure and of the Nd, and Tb-doped SrF₂ were by a factor of 2–4 higher than that of the TLD-100 and that of SrF₂:Tm was slightly lower. The main emission bands of SrF₂:Pr³⁺ are located in a convenient spectral region between 460 and 640 nm, where most of the standard photomultipliers are sensitive. The dose dependence of the 460 K TL peak in SrF₂:Pr³⁺ is nearly linear in a wide range up to above 27 000 Gy.     

Vacuum ultraviolet spectroscopy of Pr in CaAl4O7, LaMgAl11O19 and SrLaAlO4

The vacuum ultraviolet spectroscopy of Pr³⁺ doped CaAl₄O₇, LaMgAl₁₁O₁₉ and SrLaAlO₄ is reported. It appears that whenever the aluminate host lattice is excited directly, mainly exciton and 4f²–4f² [³P₀] Pr³⁺ emission are observed. When the excitation energy is lower, Pr³⁺ ions are excited selectively and 4f5d–4f² emission dominates. These observations can be explained by assuming that energy transfer from the host lattice to the Pr³⁺ ion takes place preferentially via an intermediate exciton state with an energy too low to reach the energetic Pr³⁺ 4f5d excited states.     

双波长Pr3+掺杂12CaO·7Al2O3的光存储特性

采用化学共沉淀法制备了Pr3+掺杂的12CaO·7Al2O3(C12A7:Pr3+)材料.通过X射线衍射(XRD)、发射光谱、激发光谱、余辉衰减曲线、热释发光及光激励发光等测试手段系统研究了C12A7:Pr3+材料的微观结构和光学性质.结果表明,C12A7是一种理想的适合Pr3+掺杂的基质材料,C12A7:Pr3+具有...     

Crystal field in rare-earth fluorides—I. Molecular orbital calculation of PrF3 parameters

Crystal field parameters have been calculated, using ab initio LCAO-MO theory, for the ion pair Pr³⁺—F⁻ at five metal ligand distances appropriate to Pr³⁺:LaF₃. The parameters are found to be twice as large as in PrCl₃, but with only half the distance dependence. In the absence of precise Pr³⁺:LaF₃ experimental parameters only qualitative agreement with experiment can be recorded. However, very good numerical agreement is obtained with the experimental covalency parameters for Yb³⁺:CaF₂, which provides a check on the methods adopted for calculating energy denominators.     

低温燃烧法制备SrMgAl10O17：Eu2+,Er3+高亮度蓝光荧光粉及发光性能研究

采用低温燃烧法合成SrMgAl₁₀O₁₇:Eu²⁺及SrMgAl₁₀O₁₇:Eu²⁺, Er³⁺蓝色发光材料, 通过X射线衍射仪 (XRD)、扫描电子显微镜 (SEM) 和荧光光谱仪 (PL) 等测试手段对所得样品进行表征. XRD及SEM测试结果表明: 利用低温燃烧法合成SrMgAl₁₀O₁₇材料具有较高的结晶度, 且微量的稀土元素掺杂不会破坏其晶体结构; PL测试结果表明: SrMgAl₁₀O₁₇:Eu²⁺ 荧光粉在300–390 nm范围内可以被有效的激发, 该波长范围与近紫外LED芯片匹配, 发射光谱分布在430–520 nm之间, 发射峰位于460 nm, 属蓝光发射材料. 共掺Er³⁺可显著增强SrMgAl₁₀O₁₇:Eu²⁺的发光强度, 且当Er³⁺的掺杂浓度为4%时,样品的发光强度最大, 较单掺Eu²⁺时样品的发光强度高出54.9%, 表明Er³⁺对Eu²⁺的发光具有良好的敏化作用, 该敏化作用的机理可以利用能量传递原理进行解释. 关键词： 低温燃烧法 10O₁₇')" href="#">SrMgAl₁₀O₁₇ 蓝光荧光粉 敏化作用     

Ba9Y2(SiO4)6: Ce3+,Mn2+荧光粉的发光特性及能量传递

利用高温固相法制备了Ba₉Y₂(SiO₄)₆:Ce³⁺,Mn²⁺(BYS:Ce³⁺,Mn²⁺)荧光粉,并通过X射线衍射(XRD)谱、激发和发射光谱及荧光寿命的测试对材料的结构、发光特性和能量传递进行了研究。在327 nm激发下,BYS:Ce³⁺,Mn²⁺发射光谱中包含2个发射峰,分别为位于407 nm的Ce³⁺的蓝紫光发射和位于597 nm的Mn²⁺的红光发射。在该体系中,发现了Ce³⁺向Mn²⁺的有效能量传递,使得Mn²⁺在597 nm处的红光发射显著提高,当x(Mn²⁺)=0.25时,BYS:Ce³⁺,xMn²⁺的能量传递效率可达39%。实验表明,该荧光粉可为紫外基白光LED提供良好的红光光源。