共查询到19条相似文献,搜索用时 46 毫秒
1.
2.
3.
4.
5.
用稀土氧化物硫化法合成了发光体(La_(0.9)Gd_(0.1))_2O_2S:Tb,(La_(0.9)Y_(0.1))_2O_2S:Tb和(Y_(0.8)Gd_(0.2))_2O_2S:Tb,用X射线、阴极射线和254nm 紫外线三种激发方式测试了不同Tb~(3+)离子浓度(每摩尔基质中含0.0001~0.1摩尔Tb~(3+))时,它们的发光性能。测定了它们的发光亮度、发光色度随激活剂Tb~(3+)离子浓度的变化,研究了在这三种发光体中Tb~(3+)离子的~5D_3→~7F_J和~5D_4→~7F_J 的能级跃迁强度随Tb~(3+)离子浓度变化的关系。最后探讨了激活剂 Tb~(3+)离子在这三种发光体中的浓度猝灭机理。 相似文献
6.
采用偏光显微镜(POM)、差示扫描量热(DSC)和X 射线衍射,对聚氧乙烯(PEO)的形态结构和热物理行为随6种镧系盐对PEO的摩尔比变化的规律进行了系统的探讨.结果表明,随六合水氯化镧系盐摩尔比的增加,PEO球晶行为、熔点和熔融热均逐渐减弱,当盐对PEO的摩尔比达到一定值时(如YbCl3·6H2 O :PEO =2 0 ) ,则PEO完全不结晶.不同的镧系盐对PEO结晶的影响程度不同.X 射线衍射分析的结果也表明PEO晶面衍射峰随Ln3+ 盐摩尔比的增加而下降,与POM和DSC结果一致的.结果还表明较高的干燥温度(6 0℃)对PEO与Ln3+ 的相互作用有促进作用.对比二次降温的试样与原始试样的结晶行为,降温后结晶试样的特征表明络合在降温结晶后还存在.红外结果表明PEO与Ln3+ 的相互作用是络合作用. 相似文献
7.
以乙酰丙酮(Hacac)、邻菲咯啉(phen)、硝酸根为配体,8-羟基喹啉为酸度调节剂合成出一个系列的镧系轻稀土四元配合物Ln(NO3)2(phen)2(CH3COCHCOCH3)(Ln=La,Ce,Pr,Nd,Sm)。配合物的结构与性质由元素分析,IR,1HNMR和TGA等表征。单晶Ce(NO3)2(phen)2(CH3COCHCOCH3)·H2O结构经由X射线衍射仪分析表明,晶体属单斜晶系,空间群P21/n,晶胞参数为a=1.11017(8)nm,b=0.98401(7)nm,c=1.34453(10)nm,β=102.0530(10)°,V=1.43641(18)nm3,Dc=1.715g·cm-3,Z=2,F(000)=742。配合物呈单核结构,中心离子Ce髥配位数为10。 相似文献
8.
通过水热反应合成5种结构新颖的配聚物:{[Ln_2(1,3-bdc)_3(H_2O)_4](DMF(H_2O}_n[Ln=Pr(1),Nd(2),Gd(3)]和{[Ln_4(1,3-bdc)_6(H_2O)_4(DMF)](DMF(2H_2O}_n[Ln=Er(4),Ho(5)](1,3-bdc:间苯二甲酸,DMF:N,N-二甲基酰胺)。通过单晶X射线衍射、红外光谱、紫外-可见-近红外(UV-Vis-NIR)光谱、荧光光谱等技术手段对产物的结构和性能进行了表征。结果表明,配聚物1~3是同构的,属单斜晶系,P2(1)/n空间群;配聚物4、5是同构的,属三斜晶系,P-1空间群。在晶体中,间苯二甲酸根采用多样的配位模式,使配聚物呈现多维的结构。除配聚物4,其余均呈现Ln(Ⅲ)的特征NIR发光,并与其UV-Vis-NIR吸收光谱相关联。 相似文献
9.
镧系离子(Nd3+、Ho3+、Er3+)与PMHFP和DAM三元配合物的制备及超灵敏跃迁的研究 总被引:1,自引:0,他引:1
镧系离子(Ln3+)同二安替吡啉甲烷(DAM)和1-苯基-3-甲基-4-苯甲酰基吡唑酮-5等β-二酮形成的三元配合物的超灵敏跃迁现象已有研究[1-3]。Ln3+同1-苯基-3-甲基-4-七氟丁酰基吡唑酮-5(PMHFP)的二元配合物已经合成[4]。本文研究Ln3+)-PMHFP-DAM体系中的超灵敏跃迁现象及其三元配合物的组成、结构和性质。 相似文献
10.
本工作合成了具有摩擦发光性能的Eu~(3+)与噻吩甲酰三氟丙酮(TTA)、吡啶类氮氧化物的混配型配合物。实验测得它们的化学式为Eu(TTA)_3(L) (L=吡啶氮氧化物,pyNO;2-(3-,4-)皮考林氮氧化物,2-(3-,4-)picNO;2,2‘-联吡啶二氮氧化物,bipyN_2O_2)。它们均为浅黄色晶体。通过电导、紫外和红外吸收光谱以及荧光光谱,研究了它们的物理—化学性质。这些配合物在365nm紫外灯照射下发出很强的红色荧光。在日光下或在黑暗中轻轻搅动或用玻棒摩擦时能发出明亮的红光。 相似文献
11.
A. V. Yakimanskii M. Ya. Goikhman I. V. Podeshvo T. D. Anan’eva T. N. Nekrasova R. Yu. Smyslov 《Polymer Science Series A》2012,54(12):921-941
The photoluminescence properties of Tb3+ and Eu3+ complexes with polymer ligands containing various kinds of complexing groups??namely, carboxyl (5?C20 mol %), pyridylquinoline (5 mol %), or pyridylnaphthyl (5 and 10 mol %) groups??in solution and block are considered. The chemical structure of a neutral comonomer (methyl methacrylate; styrene; isopropyl-, phenyl-, or benzylmethacrylamide; and N-vinylamides) in polymer ligands is varied. The intensity of photoluminescence is dependent not only on the chemical nature of a complexing group but also the chemical nature of a neutral comonomer and a spacer. Variation in the nature of a comonomer and a ligand makes it possible to prepare complexes in which a high luminescence of a low-molecular-mass complex is preserved and advantages inherent in a polymer complex are acquired. The effect of the nature of the polymer matrix (photoactive and photoinert) on the efficiency of electronic-excitation energy transfer is ascertained. The data on the photoluminescence of metal-polymer complexes that are based on polymer ligands containing vinylcarbozole units and that possess hole conductivity make it possible to regard them as materials for electroluminescence. The intensity of photoluminescence of these complexes is related to the competition of oppositely directed photophysical processes in a macromolecule: formation of excimers and migration of electronic excitation energy. An analysis of the published data and of the results of the authors shows that detailed studies of these polymer systems in solution and in matrices are needed to gain insight into the relationship between photo- and electroluminescence properties of metal-polymer complexes, because the matrix plays different roles in photoluminescence and electroluminescence (inner filter or conduction); as a consequence, the emission spectra may differ appreciably. It is shown that the efficiency of electroluminescence may be improved if the transfer of energy from the lanthanide ligand in a complex to the conducting matrix is decreased. 相似文献
12.
采用分步组装策略,利用3-位和4-位吡啶端基化的三脚配体,合成了分立的单核Ln(Ln=Tb/Sm/Yb)配合物,进一步通过吡啶端基的配位扩展,分别组装得到不同拓扑的Ln-M(M=Ag或Cd)三维金属-有机框架(MOF)结构。异核MOF保留了Ln配位中心的特征可见至近红外发光,并因配体能级结构和与稀土离子间的能量传递效率的改变,对配合物的发光性能产生调控。其中配合物2-Yb-Ag中,Yb的近红外发光与单核稀土配合物相比明显增强,荧光寿命从单核的4.3μs增加到6.7μs,而4-Tb-Cd则产生了配体发光与稀土中心发光的组合模式,其中来自Tb中心的荧光寿命从相应单核配合物中的2.91 ms缩短至0.62 ms。 相似文献
13.
Strong Stokes and Upconversion Luminescence from Ultrasmall Ln3+‐Doped BiF3 (Ln=Eu3+, Yb3+/Er3+) Nanoparticles Confined in a Polymer Matrix 下载免费PDF全文
Heavy metal fluorides like BiF3 as a host for lanthanide ions are of interest as bismuth is the only heavy metal that is nontoxic. In this work, we report the synthesis of highly water‐dispersible ultrasmall BiF3 nanoparticles about 6 nm in size within a poly(vinyl pyrrolidone) matrix by a hydrothermal method. Microscopy analysis reveals that the nanoparticles are well separated and confined within the polymer network. These nanoparticles were found to be excellent hosts for lanthanide (Ln3+) ions. Through suitable Ln3+ doping, BiF3 exhibits strong emissions in the visible region upon both UV and near infrared (NIR) excitations. The non‐toxicity of both bismuth and PVP can be advantageous for the potential use of BiF3 nanoparticles in drug delivery and bioimaging. 相似文献
14.
Figuerola A Diaz C Ribas J Tangoulis V Granell J Lloret F Mahía J Maestro M 《Inorganic chemistry》2003,42(2):641-649
The reaction of Ln(NO3)3.aq with K3[Fe(CN)6] or K3[Co(CN)6] in N,N'-dimethylformamide (DMF) led to 25 heterodinuclear [Ln(DMF)4(H2O)3(mu-CN)Fe(CN)5].nH2O and [Ln(DMF)4(H2O)3(mu-CN)Co(CN)5].nH2O complexes (with Ln = all the lanthanide(III) ions, except promethium and lutetium). Five complexes (Pr(3+)-Fe3+), (Tm(3+)-Fe3+), (Ce(3+)-Co3+), (Sm(3+)-Co3+), and (Yb(3+)-Co3+) have been structurally characterized; they crystallize in the equivalent monoclinic space groups P21/c or P21/n. Structural studies of these two families show that they are isomorphous. This relationship in conjunction with the diamagnetism of the Co3+ allows an approximation to the nature of coupling between the iron(III) and the lanthanide(III) ions in the [Ln(DMF)4(H2O)3(mu-CN)Fe(CN)5].nH2O complexes. The Ln(3+)-Fe3+ interaction is antiferromagnetic for Ln = Ce, Nd, Gd, and Dy and ferromagnetic for Ln = Tb, Ho, and Tm. For Ln = Pr, Eu, Er, Sm, and Yb, there is no sign of any significant interaction. The isotropic nature of Gd3+ helps to evaluate the value of the exchange interaction. 相似文献
15.
Figuerola A Diaz C Ribas J Tangoulis V Sangregorio C Gatteschi D Maestro M Mahía J 《Inorganic chemistry》2003,42(17):5274-5281
The reaction of Ln(NO(3))(3).aq with K(3)[Fe(CN)(6)] or K(3)[Co(CN)(6)] and 2,2'-bipyridine in water led to five one-dimensional complexes: trans-[M(CN)(4)(mu-CN)(2)Ln(H(2)O)(4) (bpy)](n)().XnH(2)O.1.5nbpy (M = Fe(3+) or Co(3+); Ln = Sm(3+), Gd(3+), or Yb(3+); X = 4 or 5). The structures for [Fe(3)(+)-Sm(3+)] (1), [Fe(3)(+)-Gd(3+)] (2), [Fe(3)(+)-Yb(3+)] (3), [Co(3)(+)-Gd(3+)] (4), and [Co(3)(+)-Yb(3+)] (5) have been solved; they crystallize in the triclinic space P1 and are isomorphous. The [Fe(3+)-Sm(3+)] complex is a ferrimagnet, its magnetic studies suggesting the onset of weak ferromagnetic 3-D ordering at 3.5 K. The [Fe(3+)-Gd(3+)] interaction is weakly antiferromagnetic. The isotropic nature of Gd(3+) allowed us to evaluate the exchange interaction (J = 0.77 cm(-)(1)). 相似文献
16.
Chantal Galaup Joëlle Azma Pierre Tisns Claude Picard Patricia Ramos Olga Juanes Ernesto Brunet JuanCarlos Rodríguez‐Ubis 《Helvetica chimica acta》2002,85(6):1613-1625
Two macrobicyclic ligands derived from an 18‐membered tetralactam ring and 2,2′‐bipyridine or 2,6‐bis(pyrazol‐1‐yl)pyridine moieties, 1 and 2 , respectively, form stable complexes with GdIII, EuIII, and TbIII ions in aqueous solution. The ligand‐based luminescence is retained in the GdIII cryptates, whereas this radiative deactivation is quenched in the EuIII and TbIII cryptates by ligand‐to‐metal energy transfer, resulting in the usual metal‐centered emission spectra. Singlet‐ and triplet‐state energies, emission‐decay lifetimes, and luminescence yields were measured. [Tb⊂ 1 ]3+ cryptate shows a long luminescence lifetime (τ=1.12 ms) and a very high metal luminescence quantum yield (Φ=0.25) in comparison with those reported in the literature for Tb3+ complexes sensitized by a bipyridine chromophore. By comparison to [Ln⊂ 1 ]3+, [Ln⊂ 2 ]3+ presents markedly lower luminescence properties, due to worse interaction between the 2,6‐bis(pyrazol‐1‐yl)pyridine unit and the metal ion. Moreover, the luminescent metal and the triplet ligand energy levels of [Eu⊂ 2 ]3+ do not match. The effects of H2O molecules coordinated to the metal centre and of thermally activated decay processes on nonradiative deactivation to the ground‐state are also reported. 相似文献
17.
18.
19.
《Journal of solid state chemistry》1986,65(2):156-167
The luminescence of several Sb3+-activated rare earth orthoborates (LnBO3Sb3+; Ln = Sc, Y, La, Gd, Lu) are reported. In all compositions the Stokes shift of the Sb3+ luminescence is rather large, resulting in rather low quenching temperatures (200 K or lower). The Stokes shift appears to be dependent on the coordination number and on the radius of the host lattice cation. This is explained from the assumed tendency of the Sb3+ ion to occupy an off-center position which becomes more apparent when the space available for the Sb3+ ion increases. The present results are compared with those on LnBO3Bi3+. It appears that the Stokes shift of the Bi3+ luminescence is more sensitive to the host lattice and is smaller than the Stokes shift of the Sb3+ luminescence. This is explained by the large radius of the Bi3+ ion compared to the Sb3+ ion. In GdBO3Sb3+ thermally activated energy transfer is observed from Gd3+ to Sb3+. 相似文献