Energy transfer between Ce3+ and Eu2+ in doped KSrPO4

Powder samples of KSrPO₄ doped with Eu²⁺ and Ce³⁺ were prepared by combustion-assisted synthesis. Their structures and photoluminescence spectra were systemically studied. Energy transfer from Ce³⁺ to Eu²⁺ was observed by investigating the optical properties from photoluminescence spectra in Eu²⁺ single doped and Ce³⁺–Eu²⁺ co-doped KSrPO₄. The enhancement of UV excitation is attributed to energy transfer from Ce³⁺ to Eu²⁺, and Ce³⁺ plays a role as a sensitizer. Ce³⁺–Eu²⁺ co-doped KrSrPO₄ powders can possibly be applied as blue phosphors in the fields of lighting and display.     

铈铕共掺高钆氧化物玻璃的发光性能及能量传递效应

在还原气氛下, 采用高温熔融法制备了Eu²⁺/Ce³⁺共掺的高钆氧化物玻璃. 荧光性能测试显示, Ce³⁺能够有效地敏化Eu²⁺的发光, 使Eu²⁺的发光强度增强了2.3倍; 测试对比了Ce³⁺ 发光的荧光寿命随Eu²⁺的掺入前后的变化情况, 计算得出Ce³⁺→Eu²⁺ 的能量传递效率可达61.5%, 并进一步探讨了其能量传递机理. 研究表明: 在高钆氧化物玻璃中, 采用Eu²⁺ 和Ce³⁺ 共掺的方法可有效地增强Eu²⁺ 的发光性能和闪烁性能. 关键词： 发光玻璃 能量传递 荧光寿命     

The effect of Gd3+ on the Eu3+ luminescence in RbGd3F10: Eu3+ compounds

Eu³⁺ luminescence is studied in the two polymorphic forms of RbGd₃F₁₀: Eu³⁺. In the phases where Gd³⁺ is partly replacedby Y³⁺ in order to obtain an independent variation of Eu³⁺ concentration, the quenching of Gd³⁺ luminescence by Eu³⁺ ions takes place very quickly with increasing Eu³⁺ concentration. So the transfer between Gd³⁺ and Eu³⁺ is very efficient. Besides, an important self quenching occurs as well between Gd³⁺ ions as between Eu³⁺ ions, showing strong interactions.     

Ce^3＋离子敏化Eu^3＋：Cr^3＋：Sm^3＋：YAG外延层的荧光现象

对Ce^3 :Eu^3 :Cr^3 :Sm^3 :YAG外延层中的荧光敏经现象进行了报道和分析，在较高浓度的Ce^3 离子掺杂时，外处层在蓝色、绿色波段出现了新的荧光谱线，可解释为在Ce^3 离子每化作用下，Eu^3 离子产生了由高位激发态能级^5Di(i=1,2,3）直接到基态能级^7Fj(j=0,1,2,3）的辐射跃迁过程，并且这种Ce^3 :Eu^3 :Cr^3 :Sm^3 :YAG外延层还是一种新颖的白色单晶荧光材料。     

Decay of the Ce3+ luminescence of LaMgAl11O19 : Ce3+ and of CeMgAl11O19 activated with Tb3+ or Eu3+

Decay measurements have been performed on the Ce³⁺ luminescence of LaMgAl₁₁O₁₉ : Ce³⁺ and of CeMgAl₁₁O₁₉ activated with Tb³⁺. For all samples, the decay was found to be nearly exponential over at least two decades, and the decay time constant was practically the same, being ≈20 ns. From these results and from quantum efficiency data of the Ce³⁺ luminescence, conclusions are drawn about the various energy transfers and quenching interactions occurring in these compounds.     

纳米晶ZrO2：Eu3＋-Bi3＋的制备及Bi3＋敏化Eu3＋特征发射的研究

采用化学共沉淀法制备了纳米晶ZrO2：Eu3＋-Bi3＋粉体,所制备的纳米晶粉体均能观测到Eu3＋离子的室温特征发射．研究了样品的晶体结构和发光性质．结果表明：经600℃煅烧后得到的纳米晶ZrO2：Eu3＋-Bi3＋粉体的晶相为四方相,经800,950及1100℃煅烧后的样品为四方相和单斜相的混合晶相．Eu3＋离子在四方相中的室温特征发射明显强于在混合相中的发射．Bi3＋离子的掺入对Eu3＋离子的室温特征发射有显著的敏化作用．     

Luminescence and energy transfer in Y2O3 CO-doped with Bi3+ and Eu3+

The emission spectra and decay times of the Y₂O₃ CO-doped with Bi³⁺ and Eu³⁺ have been investigated using site-selective excitation and time-resolved spectroscopy in the temperature range 8–296 K. Evidence for an energy transfer from Eu³⁺(S₆) to Eu³⁺(C₂) is given. The critical transfer distance R₀ = 8.6 Å was found from the decay curve.     

Intermolecular energy transfer from UO2+2 to Eu3+ in solutions

The quenching constants for the UO²⁺₂ ion fluorescence by the Eu³⁺ ion in H₂O, D₂O, potassium formate and acetic acid media were determined by measuring the decrease in intensity of the 5050 Å fluorescence peak and the lifetime of the UO²⁺₂ ion fluorescence. The energy transferred to the Eu³⁺ ion was found to be a small fraction of the energy lost by the UO²⁺₂ ion by the non-radiative processes. The variations of the quenching constants of the UO²⁺₂ ion and the fluorescence lifetimes were determined for different concentrations of potassium formate and acetic acid. These results indicate that the UO²⁺₂ ion forms inner sphere complexes with the two ligands mentioned.     

The ground state splitting in Gd3+ and Eu2+

The ground state of Eu²⁺ is derived from recently published data and used to verify the existenc of cancellation between different mechanisms causing the ground state splitting of these ions.     

Quantum efficiency of non-radiative energy transfer from Eu3+ → Pr3+ in calibo glass

Study of energy transfer from optically excited Eu³⁺ to Pr³⁺ has been carried out in calibo glass. Probabilities (P_da) and efficiencies (η_T) of energy transfer from Eu³⁺ to Pr³⁺ have been calculated from the life time and emission intensity of Eu³⁺ + Pr³⁺. At low acceptor concentrations, P_da varies linearly with C_a showing migration of energy among donors. At high acceptor concentrations, P_da depends linearly on (C_a + C_d)², which is consistent with Fong and Diestler theory of dipole-dipole mechanism of energy transfer. At low temperatures the probability and the efficiency decrease due to increase in the emission intensity and life time, which suggests that at room temperature the energy is transferred to lattice by donor lowering life time and intensity. At high temperatures no emission from higher levels of donor is obtained which suggests blurring out of energy levels in glassy matrix.     

Eu2+,Mn2+在BaZnP2O7中的发光及Eu2+→Mn2+能量传递

采用高温固相法合成了BaZnP₂O₇:Eu²⁺,Mn²⁺荧光粉,并对其发光性质及Eu²⁺对Mn²⁺的能量传递机理进行了研究.Eu²⁺和Mn²⁺在380 nm和670nm的发射峰分别由Eu²⁺的5d—4f跃迁和Mn²⁺的⁴T₁(^{4关键词： 磷酸盐 2+}')" href="#">Eu²⁺ 2+')" href="#">Mn²⁺ 能量传递     

Na_2CaSiO_4:Sm~(3+),Eu~(3+)荧光粉的发光特性和能量传递

利用高温固相法合成Na_2CaSiO_4:Sm~(3+),Eu~(3+)系列荧光粉末,研究了Sm~(3+)和Eu~(3+)掺杂对Na_2CaSiO_4晶体结构的影响、材料发光特性以及存在的能量传递现象.X射线衍射结果表明Sm~(3+)和Eu~(3+)单掺及共掺样品均为单相的Na_2CaSiO_4结构,晶体结构没有改变.Na_2CaSiO_4:Sm~(3+)荧光样品在404 nm激发波长下呈现峰峰值为602 nm的橙红色荧光,来源于~4G_(5/2)→~6H_(7/2)跃迁.Na_2CaSiO_4:Eu~(3+)荧光样品在395 nm激发波长下发射出峰峰值为613 nm的红色荧光.对光谱和荧光寿命的测试和分析结果表明Sm~(3+)与Eu~(3+)之间存在能量传递,通过理论计算得到Sm~(3+)和Eu~(3+)之间的能量传递临界距离为1.36 nm,相互作用形式为电四极-电四极相互作用.随着Eu~(3+)掺杂浓度的增加,能量传递效率也逐渐提高至20.6%.     

Eu2+,Mn2+在BaZnP2O7中的发光及Eu2+→Mn2+能量传递

采用高温固相法合成了BaZnP₂O₇:Eu²⁺,Mn²⁺荧光粉，并对其发光性质及Eu²⁺对Mn²⁺的能量传递机理进行了研究.Eu²⁺和Mn²⁺在380 nm和670nm的发射峰分别由Eu²⁺的5d—4f跃迁和Mn²⁺的⁴T₁(^{4相似文献}   

Ce3+/Tb3+/Sm3+共掺CaO-B2O3-SiO2玻璃的光学性能调控

采用高温熔融法制备了Ce³⁺/Tb³⁺/Sm³⁺掺杂的CaO-B₂O₃-SiO₂（CBS）发光玻璃。通过傅利叶红外光谱仪、荧光光谱仪表征了该系列发光玻璃的微观结构和发光性质,并对Ce³⁺到Tb³⁺、Ce³⁺到Sm³⁺之间的能量传递机制进行了研究。结果表明,在339,378,407 nm激发下,单掺Ce³⁺、Tb³⁺和Sm³⁺的CBS玻璃分别发射紫蓝光、绿光和红光,恰好符合混合合成白光的条件。Ce³⁺/Tb³⁺和Ce³⁺/Sm³⁺双掺CBS玻璃的发射光谱以及Ce³⁺衰减寿命的变化证实了Ce³⁺→Tb³⁺和Ce³⁺→Sm³⁺之间存在能量传递,随Tb³⁺和Sm³⁺浓度增加,Ce³⁺的寿命减小,且传递效率由5.4%和5.7%分别增加至24.0%和27.1%。调节3种稀土离子的掺杂浓度并选择合适的激发波长,实现了发光颜色可调,并最终获得白光发射。     

Method for fitting crystal field parameters and the energy level fitting for Yb3+ in crystal Sc2O3

<正>A method to compute the numerical derivative of eigenvalues of parameterized crystal field Hamiltonian matrix is given,based on the numerical derivatives the general iteration methods such as Levenberg-Marquardt,Newton method, and so on,can be used to solve crystal field parameters by fitting to experimental energy levels.With the numerical eigenvalue derivative,a detailed iteration algorithm to compute crystal field parameters by fitting experimental energy levels has also been described.This method is used to compute the crystal parameters of Yb~(3+) in Sc_2O_3 crystal, which is prepared by a co-precipitation method and whose structure was refined by Rietveld method.By fitting on the parameters of a simple overlap model of crystal field,the results show that the new method can fit the crystal field energy splitting with fast convergence and good stability.     

近红外光诱导下NaYbF4:Tm3+,Eu3+ 体系中Eu3+的上转换发光

利用水热法制备得到NaYbF₄:0.01%Tm³⁺,20%Eu³⁺上转换材料,利用X射线衍射分析、扫描电子显微镜及光谱测试技术分别对其进行了结构、形貌以及光谱性质的表征。在980 nm近红外激光激发下,得到了Eu³⁺的可见到紫外范围的上转换荧光发射。分析表明:共掺杂NaYbF₄纳米材料中Tm³⁺到Eu³⁺离子的能量传递对布居Eu³⁺离子的激发态能级,获得Eu³⁺的上转换发光起着至关重要的作用。另外,在实验中首次获得了Eu³⁺对应于³P₀→⁷F_j (j=0,1,2)能级跃迁的上转换光发射。     

Magnetic properties of paramagnetically doped crystals Fe3+, Nd3+ and Ho3+ in various compounds

In this work we calculate the energy levels, wave functions and transition probabilities for a number of compounds whose crystal field parameters have been determined. We introduce a convergence criterion in the diagonalization of the Hamilton matrices dependent upon a self consistency test on the eigenvectors. This assures us of numerically accurate wave functions.First we calculated energy level and susceptibility differences in (Nd³⁺)PbMoO₄ dependent on the multiplicative constants θ_n, used with the published A_l^m to determine the crystal field parameters B_l^m, (B_l^m = θ_nA_l^M). Calculated energy levels as a function of external magnetic field strength and orientation are compared with experimental results for three different sets of published crystal field parameters, B_l^m, for (Fe³⁺)TiO₂. The ground state energy levels, and wave functions, have been calculated for the non-Kramers Ho³⁺ ion in the crystals PbMoO₄, LaCl₃ and HoCl₃. Easily distinguishable variations in the temperature dependence of the X_zz component of the susceptibility are found as a function of the host crystal. It is pointed out that susceptibility calculations, based upon measured crystal field parameters, in conjunction with subsequent susceptibility measurements, provide a good check on the validity of the crystal field parameters.