YBO3：Eu中发光中心的格位与晶场拟合

通过对溶胶－凝胶法制备的YBO3：Eu的光致发射谱进行分析,证实Eu^3 可能占据两种晶场格位。并采用晶场拟合的方法定量确认这两种晶场格位的对称性分别为C3v和D3,这种指认下能级的拟合结果以及点群选择律和实验结果相当吻合。     

YBO_3∶Eu荧光粉的水热法制备及形貌控制

用水热法在低于 3 0 0℃成功地制备出具有不同形貌的 YBO3∶ Eu3+ 荧光粉 ,其反应温度比固相反应降低了约 80 0℃ .研究了初始原料、p H值、反应温度、反应溶剂和催化剂等条件对目的产物形貌及粒度的影响 ,得到了具有 Vaterite结构、粒度分布均匀的球形荧光粉的最佳合成工艺 .在 2 5 4nm激发下 ,水热法制备的球形 Y0 .95Eu0 .0 5BO3荧光粉最强发射峰位于 5 98nm处 ,属于 Eu3+ 的 5D0 →7F1 的跃迁 ,是固相反应所得样品的 1 .5倍 .这些结果表明 ,在 PDP和荧光灯等显示和照明用荧光粉的制备中水热法具有潜在的应用前景 .     

球形La2O3∶Eu纳米晶的制备及其发光特性

近年来纳米材料的发展及纳米材料所具有的特异的光学性质,使得纳米发光材料引起越来越多的关注。La2O3结构简单,易于合成,价格便宜．因此以La2O3为基质的发光材料已有很多报道。Mekittric等研究认为,发光材料的形貌,如颗粒度、形状、结晶性等．是影响发光效率的一个重要因素．球形颗粒可以提高其密堆性．从而能有效地提高产品的发光亮度。     

KMgF3∶Eu和KMgF3∶Eu-Ce单晶体中Eu2+与Ce3+的格位取代和能量传递

在77 K测定了两个晶体的高分辨发射光谱, 讨论了单掺杂Eu2+ 和双掺杂Eu2+ 及Ce3+ 的KMgF3中的格位取代问题. 在KMgF3∶Eu-Ce中观察到了Eu2+ 的6P5/2能级到Ce3+ 的 4f5d 能级间的间接能量传递, 讨论了能量传递机理.     

特殊的GdVO_4∶Eu~(3 )发光的温度特性

ＧｄＶＯ4 作为良好的激光基质被广泛研究 ,Ｇｄ ＶＯ4 掺Ｐｒ3 ,Ｎｄ3 ,Ｈｏ3 ,Ｅｒ3 ,Ｔｍ3 ,Ｙｂ3 的激光材料已有报道[1～ 4 ] 。虽然ＧｄＶＯ4 ∶Ｅｕ3 不是激光材料 ,但它是良好的红光材料 ,主峰发射位于 619ｎｍ。ＧｄＶＯ4 ∶Ｅｕ3 的发光强度高 ,与Ｙ2 Ｏ2 Ｓ∶Ｅｕ和ＹＶＯ4 ∶Ｅｕ的发光为同一量级[5] 。Ｇｄ3 Ｅｕ3 是研究能量传递的极好体系。通常发光体的发射强度是随着温度的升高而降低的 ,最近的实验表明ＧｄＶＯ4 ∶Ｅｕ3 的发光强度随着温度的升高不但不降低反而不断增强 ,且温度高达 60 0Ｋ都尚未见饱和。1　 实　验实…     

花瓣形YBO3:Eu3+发光薄膜的制备与表征

稀土正硼酸盐(REBO3)在真空紫外光谱区具有很好的透明性和高的损伤阈值,是重要的VUV荧光材料基质[1,2].例如,YBO3∶Eu3 在VUV光谱区有强的吸收和很好的发光效率,是目前最好的红色VUV荧光材料之一.     

掺Eu3+离子Y2SiO5晶体格位选择光谱研究

分别利用白光灯、４５７－９ ｎｍ 氩离子激光、二倍频ＹＡＧ∶Ｎｄ 激光泵浦的诺丹明６Ｇ 可调谐窄线宽（０－５ ｃｍ －１） 染料激光作为光源， 以单色仪锁相放大器光电倍增管计算机数据采集系统记录光谱， 测量并研究了Ｙ２ＳｉＯ５∶Ｅｕ３ ＋ 晶体的透射光谱、荧光光谱、激发光谱和格位选择荧光光谱。５Ｄ０ →７Ｆ０，１ ，２ ，３，４ 跃迁，３０ 多根谱线（总数为５０ 根） 被观察到。在该晶体中Ｅｕ３＋ 替换Ｙ３＋ 离子， 占据两个较低对称性的光学格位， 这两个格位的５Ｄ０ ７Ｆ０ 能级跃迁谱线相隔大约只有０－２ ｎｍ ， 在室温下有一定的光谱关联。并用Ｘ射线谱对晶体的晶格常数ａ ， ｂ，ｃ 和晶面角度β进行测量， 测量结果显示掺杂后的晶格常数和未掺杂的Ｙ２ＳｉＯ５ 晶格常数基本一致。     

表面活性剂组装的Y2O3∶Eu纳米管及其位置选择光谱

利用表面活性剂为模板, 通过自组装制备出了具有管状结构的Y2O3∶Eu纳米材料. 透射电子显微镜证实了管状结构的形成. 在紫外光的激发下, Y2O3∶Eu纳米管表现出与纳米颗粒不同的发光性质. 由电荷迁移带和低温下的激光选择激发光谱可以推测, 处于纳米管壁内部的发光中心具有较为确定的格位对称性, 其发射光谱具有清晰的光谱结构. 由于表面缺陷的存在, 纳米管壁近表面的Eu3+离子处于较为复杂的微环境中, 其发射光谱表现为非均匀展宽的光谱线形.     

LiNbO_3晶体中Nd~(3+)离子的配位场能级计算

运用双层点电荷配位场模型和点电荷模型计算了C3v对称场中LiNbO3∶Nd3+晶体的52个配位场能级,2种模型计算的均方根偏差分别为49.32和62.75cm-1.双层点电荷模型的拟合结果与实验结果更吻合,计算所得晶体场参数B6m值也明显好于点电荷模型,说明双层点电荷模型能够更好地反映中心离子和配体之间相互作用的真实情况,这对于研究C3v对称场中稀土离子的光谱特性具有非常重要的意义.     

稀土红色荧光粉SrZnO2∶Eu3+的发光性能

Eu3+红色荧光激活剂的发光性能引人注目.Eu3+掺杂的YVO4、Y2O3、Y2O2S等红色发光材料,已广泛应用于各种彩色显示和照明领域[1].寻找对长波紫外光能有效吸收且性能稳定的无机稀土荧光体是当前研究的重要方向[2].     

The Site Symmetry of Eu~(3 ) in ZnS:Eu Nanoparticle

IntroductionNanosizedZnSmaterialsdopedornotdopedwithimpuritieshavebeenpreparedandstudiedl3.Chenandhiscoworkers4studiedandreportedthethermoluminescence(TL)ofZnSnanoparticles.TheyfoundthatboththeTLandthesurfacefluorescenceincreaseastheparticlesizeisdecreased,andtheTLisrelatedtothesurfacestates.Mn-dopedZnSnanoparticlesyieldthebestexternalphotoluminescentquantumefficiencyofabout18%atroomtemperatureandluminescentdecaytimeisatleastfiveordersofmagnitudefasterthanthatofthecorrespondingMn2 radiat…     

Crystal Structure of Scheelite-type LiTb(WO_4)_2 and Multi-color Emitting Properties Doped by Eu~(3+)

Single crystal of lithium terbium tungstate LiTb(WO4)2 has been grown by the flux method. The crystal structure was refined from single-crystal X-ray data. It crystallizes in tetragonal system, space group I41/a with a = 5.1749(9), c = 11.1953(19) ?, V = 299.81(12) ?~3, Z = 2, Mr = 661.56, Dc = 7.328 g/cm^3, F(000) = 560, μ(MoKα) = 49.94 mm^-1, R(F^2 > 2σ(F^2)) = 0.026 and wR(F^2) = 0.070. It features a typical scheelite-type structure composed of two-direction packing of isolated WO4 tetrahedra. Li and Tb atoms in the structure occupy the same crystallographic site. Moreover, a series of solid solution phosphors LiTb(1-x)Eux(WO4)2(x = 0.004~0.1) were synthesized by high temperature solid-state reactions. The phosphors could be effectively excited by a wavelength range from 379 to 487 nm, which matches well with the UV and near-UV LED chip. The emission color of the phosphor can be tuned from green, through yellow to red by simply adjusting the relative Eu³⁺ and Tb³⁺ concentration due to the Tb³⁺ to Eu³⁺ energy transfer.     

Eu~(3+)掺杂铌硅玻璃的微观局域环境特性

研究了Eu3+掺杂铌硅玻璃的5D0发射光谱,其激发谱中7F0 5D2声子边带,荧光窄化谱及5D0能级寿命。并由此计算了强度参数与晶场参数。结果显示5D0 7F2 5D0 7F1发光强度之比与强度参数Ω2随着Nb2O5浓度的增加而增大,表明材料对称性降低,Eu-O键强增加,共价性增强。晶场参数B20随着Nb2O5的浓度增加而减小,同样表明Eu-O键的距离减小,键强增加。随着Nb2O5的浓度增加,电 声子耦合增强,5D0能级的无辐射过程加快,寿命变短。     

KZnF3：Eu^3＋单晶生长及光谱特性

利用Ｂｒｉｄｇｍａｎ－Ｓｔｏｃｋｂａｒｇｅｒ方法在氩气气氛下生长出ＫＺｎＦ３：Ｅｕ＾３＋单晶，测定了晶体的激发光谱、荧光发射光谱和ＥＳＲ谱，讨论了Ｅｕ离子的取代格位。     

三角对称晶场中 4 A2(3d3 )态离子EPR参量的SS和SOO机制

A CDM/ EPR program has been developed using Visual Basic 6. 0. The spin-spin（SS）and spin-otherorbit（SOO）interactions omitted in published works have also been included in the Hamiltonian. The CDM/EPR program can study not only the EPR parameters but also the CF energy levels and wavefunctions for 4A2 （3d3）states ions in crystals. Utilizing the CDM/ EPR program,the EPR parameters and fine spectra for Ruby and Emerald have been investigated. The theoretical results are in good agreement with the experimental findings. The contributions to the EPR parameters and fine spectra arising from SS and SOO interactions have been studied. The investigation shows:① The EPR parameters are mainly induced by SO coupling interaction;② The contribution to the zerofield-splitting（ZFS）arising from SS interaction is appreciable and cannot be omitted,whereas the contributions to the ZFS parameter D arising from SOO interaction are smaller;③ The contribution to the Zeeman g-factors and spectra arising from SS and SOO interactions is slight.     

Synthesis,Crystal Structure and Luminescent Property of an Eu~(3+) Complex

A new Eu(Ⅲ) complex, {[Eu(tta)2(C2H5OH)(NO3)]2(bmp)}·bmp(tta = 2-thenoyltrifluoro- acetonate, bmp = 2,2'-bipyrimidine), has been synthesized and characterized by elemental analysis, IR, luminescence and single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic P21/n space group, with a = 11.894(6), b = 14.235(8), c = 19.078(10) , β = 103.423(9)o, V = 3142(3) 3, Z = 2, Mr = 1721.10, Dc = 1.819 g/cm3, F(000) = 1696, the final R = 0.0452 and wR = 0.1398 for 5375 observed reflections with I 2σ(I). In the complex, each Eu(Ⅲ) ion is coordinated with four oxygen atoms from two tta ligands and two nitrogen atoms from a bmp ligand, three oxygen atoms from one NO3- anion and one ethanol molecule, forming a distorted tricapped trigonal prism geometry. Luminescence measurement indicates that the europium complex is a strong red emitter in the solid state at room temperature.     

Eu~(3 )在CaYBO_4中的取代和发光

用固相法制备化合物CaY1 -xBO4∶xEu ,研究Eu3 在CaYBO4中的取代格位和发光特性。当Eu3 掺杂浓度不大时 ,存在两个发光中心 ,认为是取代基质中有两个Y格位的结果 ;通过对Eu O的电荷迁移激发带位置的分析 ,表明Eu3 所处八面体中心格位的对称性越低 ,Eu O的电荷迁移带越偏向于短波 ;当Eu3 的掺杂浓度较大 (x >0 1 0 )时 ,Eu3 离子也可占据Ca2 格位 ,同时Eu3 还原成Eu2 。     

Growth and Spectral Properties of Nd^3＋ Doped KLa（MoO4）2 Crystal

1 INTRODUCTION There has been an increasing interest in the re- search of diode-pumped solid-state lasers in recent years because of the rapid development of high power diode lasers. The absorption peak of Nd3 ions at about 800 nm corresponding to 4I9/2→ 2H9/2 tran- sition is suitable for commercial laser diode GaAlAs pumping[1]. KLa(MoO4)2 is a kind of disordered crystalline host for lasing rare-earth ions[2], and it belongs to Scheelite (CaWO4) structure[3]. The disorder derives…