Eu3+在La2O2S中的长余辉发光

The new Eu³⁺ doped lanthanum oxysulfide phosphors,which have the orange-red long afterg low emission,were synthesized by solid-state reaction method.The synthesized phosphors were characterized by X-ray diffraction.The excitation and emission spectra,afterglow spectra and afterglow decay curves were examined.XRD confirmed the phosphor as pure phase La₂O₂S.The phosphors showed typical transitions ⁵D_J(J=0,1) → ⁷J_J(J=0,1,2,3,4)of Eu³⁺.The photoluminescence spectra and afterglow spectra presented the regular alteration with various Eu³⁺ concentration, due to cross relaxation between energy levels of Eu³⁺. In addition, we studied the effects of activator concentration and dopants species on the afterglow property. The data showed afterglow result was the best with 2 % Eu³⁺ and doped with Mg²⁺ and Zr⁴⁺. A prominent phosphorescence can be seen in this phosphor after illuminated with UV light.     

沉淀法合成纳米晶长余辉材料Y2O2S∶Eu3+，Ti

The long-lasting phosphorescent materials, yttrium oxysulfides doped by Eu and Ti, were systhesized by coprecipitation with their subsequent thermal decomposition in the presence of sulphur. The products were characterized by XRD, TEM, phosphorescent spectra, and thermoluminescence. The XRD results indicate that the lowest synthesis temperature is 700 ℃. From the TEM, the average diameter of particles was in the range of 60～120 nm, and augmented with the increase of temperature. The materials under UV excitation presented well afterglow from the transition of ⁵D_0,1 → ⁷F_J of Eu³⁺, and the persistent time was about 2 h. The long-lasting afterglow mechanism was discussed, too.     

Theoretical Analyses of 4f11 →4f105d Excitation Spectra of Er3+ Doped in LiYF4

Spectral terms and J-spectral multiplet of low-spin 4f^105d configuration of Er^3 were obtained with the method of ligand field theory. According to the selection rules for dipole transitions, the excitation spectra of Er^3 doped in LiYF4 in vacuum ultraviolet region (120～160nm) of the spectrum were theoretically interpreted by applying the crystal field model, and the six bands were assigned to the spin-allowed transitions from the ground state (^4I15/2) to J-spectral multiplet of low-spin 4f^105d configuration of Er^3 ion.     

High-temperature High-pressure Hydrothermal Synthesis of Dy3＋-doped YNbO4 Single Crystal and Its Luminescence Properties

Single crystal Dy3＋ doped YNbO4phosphors were prepared via a high-temperature high-pressure hydrothermal procedure. Under excitation at 270 nm, the Dy3＋-doped YNbO4 phosphor shows bright white emission, which is composed of two strong bands at 492 and 576 nm corresponding to the characteristic 4F9/2→6H15/2 and aF9/2→6H13/2 transitions of Dy3＋, respectively. The dominant band was observed at 352 nm, which corresponds to the 6H15/2→6p7/2 transition of Dy3＋. Nearly white light was achieved at 2ex 270, 310 and 388 nm and the CIE（International Commission on Illumination） values were （0.3135, 0.3421）, （0.3088, 0.3380） and （0.3146, 0.3296）, respectively.     

一种黄绿光LED用荧光粉：Ga2S3∶Eu2+

Eu²⁺-activated Ga₂S₃ phosphors were synthesized by solid-state reaction and their luminescence properties were studied with diffuse reflection spectroscopy, excitation spectra, emission spectra and fluorescence lifetime. The parameters of LED manufactured with phosphors Ga₂S₃∶Eu²⁺ were measured. The excitation spectra of these phosphors are broadband and can be matched with the emission wavelength of GaN chip.     

溶剂热合成纳米球状La2O2S：Eu^3＋荧光粉

Nano-sphere-like Eu^3 activated lanthanum oxysulfide phosphor was first synthesized directly by solvothermal method. The phosphor was characterized by XRD, TEM and PL. Photoluminescence spectra indicate that this phosphor showed three typical transitions of Eu^3 (^5Do→^7F^1,^5D0→^7F2,^5D0→^7F4). In comparison with those prepared by high temperature solid state method, photoluminescence spectrum of Eu^3 (^5D0→^7F2)-doped nano-La2O2S：Eu^3 phosphor became broader. And the reaction mechanism was also mentioned in this paper.     

新型荧光粉Ca2Zn4Ti16O38∶Pr3+，Na+的合成和红色长余辉性质

采用溶胶-凝胶法合成了Ca2Zn4Ti16O38:Pr3+,Na+荧光粉.通过X-射线衍射和荧光光谱表征样品的物相组成和发光性质.X射线衍射(XRD)分析表明添加适量的H3BO3作助熔剂有利于形成良好的Ca2Zn4Ti16O38晶体结构.荧光光谱表明Ca2Zn4Ti16O38:Pr3+,Na+在可见光区(450～495 nm)呈现Pr3+离子的4f→4f厂特征激发光谱以及613 nm(1D2→3H4)和644 nm(3P0→3F2)特征发射.Ca2Zn4Ti16O38:Pr3+,Na+被可见光(475 nm)激发产生的(3P0→3F2)(644 nm)红色发射呈现出极慢的衰减特性.Ca2Zn4Ti16O38:Pr3+,Na+是一种新型的可见光激发红色长余辉荧光粉.     

Ba3LaNa(PO4)3F:Tm3+, Dy3+: A tunable blue-white color emitting phosphor via energy transfer for UV white LEDs

A series of Tm^3+/Dy^3+co-doped Ba3 LaNa(PO4)3 F(BLNPF) phosphors were synthesized successfully via a high-temperature solid-reaction,and luminescence properties were investigated.Upon near violet excitation,BLNPF:Tm^3+,Dy^3+ phosphors exhibit Tm^3+:^1D2-^3 F4 and Dy^3+:^4 F(9/2)-^6 HJ(J=15/2,13/2,11/2)transitions with diffe rent luminescence intensity.The emitting color of the obtained products was found to shift from blue to white as a result of efficient energy transfer(ET) from Tm^3+to Dy^3+ions.According to photoluminescence emission intensity,the positive effect of activator on ET efficiency was calculated and the maximum ET efficiency was found around 72.6% with Dy^3+ concentration was 0.04.By means of Dexter's theoretical model,furthermore,dipole-dipole interaction was confirmed as the mechanism of energy transfer from Tm^3+ to Dy^3+ ions.The results suggested that BLNPF:Tm^3+,Dy^3+ phosphor might be a promising single-phased white-light-emitting phosphor for UV white-light LED.     

CaWO4中Eu3+的长余辉发光

Eu³⁺ activated CaWO₄ was prepared by high temperature solid state reaction technique. Red afterglow was observed for in the CaWO₄∶Eu after exciting with 254 nm light due to Eu³⁺ transition from ⁵D₀ to ⁷F_J (J=0, 1, 2, 3,4). By the calculation of the thermoluminescence spectrum of CaWO₄∶Eu, we conclude that there were two types of trap centers: V_Ca″ was formed by substitution of Ca²⁺ by Eu³⁺ and complex traps were produced because of substitution of W⁶⁺ by Eu³⁺.     

Surface-treatment of Alkaline Earth Sulfides Based Phosphor

A series of alkaline earth sulfides based phosphors Ca0.8Sr0.2S : Eu^2 , Tm^3 were covered with a layerof protective coating with alkaline earth fluorides by heating the mixture of phosphor and NH4HF2 at elevatedtemperatures. The coatings were characterized by means of XRD and SEM. The optical properties of thecoated phosphors and the influences of the coating on their properties have been discussed extensively. Thestabilities of the coated and uncoated phosphors have been compared.     

The turn-off fluorescent sensors based on thioether-linked bisbenzamide for Fe3+ and Hg2+

Some dibenzamide derivatives with a thioether linker were designed, synthesized and characterized. The specific responses to Hg²⁺ and Fe³⁺ were investigated by fluorescence. According to fluorescence titration, the Job plot, ¹H NMR, and ESI-mass analysis, the derivative with mono-hydroxyl substituent (1b) on the aromatic ring has high selectivity for Fe³⁺ ion with the formation of 1:1 1b-Fe³⁺ complexes. The specificity of 1c for Hg²⁺ could be switched by swapping the substituent from hydroxyl to amino, and a 1:2 (1c-Hg²⁺) complex was formed. Along with the obtained results, density functional theory (DFT) and natural bond orbital (NBO) analyses, Time-dependent (TD) DFT and natural transition orbital (NTO) analyses were employed to explore the geometric structures, properties and possible mechanisms.     

Zur elektrochromatographischen Trennung von Y3+, La3+, Ce3+, Pr3+ und Nd3+

Ohne Zusammenfassung     

Die Reaktion von Arsenazo III mit H+, La3+, Sm3+, Gd3+, Dy3+ und Yb3+

Ohne Zusammenfassung     

Sensitization of Tb3+ luminescence with Ce3+ in LaOBr: Tb3+, Ce3+

Luminescence emission and uv-excitation properties of LaOBr: Tb³⁺, LaOBr: Ce³⁺, and LaOBr: Tb³⁺, Ce³⁺ phosphors were studied. The visible emission spectra of La_0.995Tb_0.005OBr consists of⁵D_3,4 →⁷F_3–6 transitions in the wavelength range of 410–630 nm. The excitation of the Tb³⁺ ion gives a broad 4f → 5d transition band at 254 nm and weaker4f → 4f transition lines above 300 nm. The uv-excitation and emission of La_0.995Ce_0.005OBr at 290, 315, 355 (excitation), and 440 nm (emission) originate from transitions between the 4f-ground state and the four crystal field components of the5d²D excited state. The sensitization of Tb³⁺ luminescence in LaOBr with Ce³⁺ at varying concentrations is described and discussed. With increasing Ce³⁺ concentration the ⁵D₃ →⁷F transitions of Tb³⁺ quench totally and the⁵D₄ →⁷F transitions begin to quench gradually. The excitation spectrum of the⁵D₄ →⁷F₅ transition of Tb³⁺ consists of four bands due to Tb³⁺ and Ce³⁺, of which the three Ce³⁺ bands increase in intensity and the Tb³⁺ band decreases as the Ce³⁺ concentration is increased.     

Er3+和Ce3+/Ce4+掺杂β-BaB2O4纳米棒的制备、结构与发光性质

以Ba(NO3)2、NaBH4、Er2O3和CeO2为原料, 在十六烷基三甲基溴化铵(CTAB)表面活性剂辅助下, 采用水热法制备了β-BaB2O4 (β-BBO)纳米棒, 稀土离子Er3+单掺杂的β-BBO(β-BBO:Er3+)及Er3+和Ce3+/Ce4+共掺杂的β-BBO(β-BBO:Er3+/Ce3+/Ce4+)纳米棒. 通过X射线粉末衍射(XRD)、傅里叶变换红外(FTIR)光谱、拉曼光谱、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和光致发光(PL)光谱分别对样品的物相、结构、形貌、成分及光致发光性质进行了表征. 研究结果表明: 微量稀土离子掺杂并不改变β-BBO的结构, 制得的纳米棒尺寸均匀, 长度在200-500 nm 之间, 直径在10-20 nm 之间; β-BBO:Er3+和β-BBO:Er3+/Ce3+/Ce4+纳米棒在400nm光激发下, 在可见光范围内都观察到中心波长为515和542 nm的绿光. 对发光机理的初步研究表明: 发光分别对应于Er3+的2H11/2→4I15/2, 4S3/2→4I15/2跃迁, 铈离子以Ce3+和Ce4+两种形式存在于体系中, Ce3+对Er3+起敏化作用, 可以显著增强β-BBO:Er3+/Ce3+/Ce4+纳米棒的发光强度, 存在Ce3+→Er3+的能量传递过程.     

以9-蒽醛为荧光基团的吡唑啉衍生物荧光探针对Fe3+和Cu2+的检测

以9-蒽醛为荧光基团,吗啉环和吡唑环为识别基团,合成了一种新型荧光探针1,5-二苯基-3-（10-（吗啉甲基）蒽-2-基）吡唑啉（PMAP）,利用¹H NMR、¹³C NMR和单晶衍射表征其结构,通过荧光发射光谱和紫外可见吸收光谱研究其离子识别性能。结果表明,探针PMAP对Fe³⁺、Cu²⁺具有良好的识别效果,荧光量子产率分别从0.14降到0.05和0.04,溶液颜色从淡黄色变为蓝色。PMAP与Fe³⁺/Cu²⁺以1∶1的化学计量比形成配合物,检测限约为1 μmol·L^-1。同时,干扰实验表明PMAP具有良好的抗干扰性能。在实际样品中的应用表明,PMAP传感器能有效地检测实际水样中的Cu²⁺和Fe³⁺。另外,根据Fe³⁺、Cu²⁺和H+不同组合时PMAP的量子产率构建了分子水平上的三输入NOR逻辑门电路。     

芳香寡聚磺酸酯桥联大环化合物的合成及其对Sn2+和Bi3+的识别作用

以4,6-二烷氧基-1,3-苯二磺酰氯和芳香二酚为原料,三乙胺作缚酸剂,二氯甲烷作溶剂,采取一步成环法合成了3种磺酸酯桥联大环化合物。合成产物的结构用IR、¹H NMR、¹³C NMR和MALDI-TOF等技术手段进行了确认。利用紫外光谱分析的方法研究了4,6,16,18-四正戊氧基-11,23-二甲基-1,3,13,15-四磺酸酯间苯芳香大环(5)对Ca²⁺、Pb²⁺及部分过渡金属等20种金属离子的识别。结果发现,其对Sn²⁺显示出一定的选择性,由于Sn²⁺和Bi³⁺协同作用的影响,在化合物5-Sn²⁺的体系中加入Bi³⁺,紫外吸收光谱在325 nm左右的吸收增强了许多,这说明化合物5对Bi³⁺显示出优于Sn²⁺的较好选择性。     

LiNbO3晶体中Yb3+的配位场能级分析

０引言自从上世纪６０年代LiNbO３晶体合成以来，人们对这种材料的兴趣越来越大。它的优良的非线性特征使LiNbO３晶体成为用于光电装置的最好的物质之一，也是信息贮存和全息照相的很好材料。稀土离子可以很容易地掺杂到该晶体中，用频率自动加倍、自猝灭开关和自动密封等方式来发展微激光。在这种意义上，Yb３＋成为主要的激光材料掺杂离子，它的光谱特征在大量体系中已有研究，已经获得了不同基质中的激光犤１～５犦。由于Yb３＋的谱带积分面积较大，所以，Yb３＋已被用作其它稀土离子的敏化剂，用以提高它们的激发效率，如：Yb－Er…     

Die Verteilungkoeffizienten von TiO2+, Cr3+, Mn2+ und Fe3+

Ohne Zusammenfassung     

Spektralphotometrische Studie der Reaktion von Gd3+, Sm3+, Dy3+ und Yb3+ mit Xylenolorange

Zusammenfassung Es werden optimale Bedingungen für die Reaktion von Xylenolorange mit Gd³⁺, Sm³⁺, Dy³⁺ und Yb³⁺ aufgefunden, die Zusammensetzung der entstehenden Komplexe als auch ihre Bildungs- und Stabilitätskonstanten festgestellt, und ein Verfahren für die Bestimmung kleinster Mengen von Seltenen Erden wird vorgeschlagen.

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Summary Optimum conditions for the reaction of xylenol orange with Gd³⁺, Sm³⁺, Dy³⁺, and Yb³⁺ are worked out, composition of the complexes and constants of formation and stability are ascertained, and a procedure for the determination ofg-quantities of rare earths is proposed.