Spectral and photochemical characteristics of CdSe nanoparticles stabilized in polymer-containing media

The optical characteristics of CdSe nanoparticles, produced in aqueous solutions and polymer films in the reaction of cadmium chloride and sodium selenosulfate, were studied. The main parameters that make it possible to vary the forbidden band width were identified. The absorption, photoluminescence, Raman, and nonstationary decolorization spectra of CdSe nanoparticles of various sizes were analyzed. It was demonstrated that under the conditions of pulsed irradiation the CdSe nanoparticles are capable of accumulating excess electrons and inducing redox transformations in components of the solution (oxygen, methylviologen, and sulfite ions). __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 3, pp. 150–155, May–June, 2006.     

Luminescence kinetic and association equilibria of lanthanide ions in aqueous solutions. II. Determination of the formation constant of Tb acetato complex by means of luminescence lifetime measurement

The association constant K of mono-acetato complex of Tb³⁺ has been determined at normal p and T conditions by measurement of its luminescence lifetime in aqueous solution containing increasing concentrations of acetate. Two experimental arrangements used for the measurement are described.     

一种计算稀土材料陷阱深度的新方法

表征陷阱材料的主要物理量是陷阱深度, 准确计算出陷阱深度对于研究陷阱材料具有重要的意义. 从能带模型出发, 利用速率方程分析了整个热释光过程, 提出了一种计算稀土材料陷阱深度的新方法, 替代以往利用单分子或双分子近似计算陷阱深度的方法. 以SrAl2O4：Eu^2＋, Dy^3＋及Sr4Al14O25：Eu^2＋, Dy^3＋材料为研究对象, 计算了陷阱深度. 研究表明, 这种计算方法能更准确、真实地描述其物理过程.     

Tb~(3 )在MO(M=Ca,Sr)中的长余辉发光

长余辉发光材料的研究与应用,已有近100年的历史,目前仍在许多领域中有着重要应用[1].此类材料与其他光致发光材料具有相同的发光性能,只是更注重其发光的衰减过程和热释光性能.如,ZnS:Cu作为黄绿色的长余辉发光材料,在1992年以前是余辉性能最好的长余辉发光材料,一直处于发光研究工作的中心.     

机械球磨与反应烧结合成Sr2CeO4发光体的研究

Sr₂CeO₄ phosphor was synthesized by mechanical milling and reactive sintering in this work. The solid state reaction of SrCO₃and CeO₂ (2∶1) started at about 850 ℃ and completed at 1 000 ℃ for about 4 h. Two types of formation mechanism of Sr₂CeO₄ were proposed. When the starting powder mixture was fired above 1 000 ℃, the unstable intermediate phase SrCeO₃was developed, which then reacted with SrCO₃to form the final product Sr₂CeO₄, however, SrCO₃and CeO₂ converted directly to Sr₂CeO₄ at a lower temperature. The XRD results showed the crystal structure of Sr₂CeO₄ was orthorhombic. The emission spectra displayed a broad band with maximum at about 465 nm. The mechanical milling of starting power mixture and the sintering temperature had no effect on this emission spectra.     

三维配位聚合物[Zn(HCO2)2(4,4''''-bipy)]∞的合成、晶体结构及性质研究

以ZnO,HCO_2H及4,4'-bipy(摩尔比1∶3∶1.25)溶于H_2O和DMF(体积比13∶1),并在60℃反应,合成了标题化合物[Zn(HCO_2)_2(4,4'-bipy)]_∞,对其进行了元素分析、红外光谱等表征,并测定了晶体结构.该化合物晶体属四方晶系,P4_32_12空间群,a=b=0.79675(5)nm,c=1.7627(2)nm,V=1.1190(3)nm~3,Z=4,Dc=1.850g/cm3,M_r=311.60,F(000)=632,μ=22.07cm-1,最终偏离因子R1=0.0183和wR_2=0.0483.该化合物中Zn原子和两个4,4'-bipy的N原子和四个甲酸根的O原子配位,形成的ZnN_2O_4八面体通过4,4'-bipy和甲酸根桥联,组成一种新颖的3D网络结构.同时,研究了该化合物的热性质和荧光性质.     

Luminescence Properties of Tb-Doped Yttrium Disilicate Prepared by the Sol–Gel Method

A sol–gel method for the synthesis of nanosized powders of yttrium disilicate doped with Tb^{3 +} is presented. The influence of grain size and annealing temperature on the structure and luminescence properties of the materials obtained has been investigated. The preparation of glass-ceramic composite has been also described. The effect of incorporating the nanocrystals into sol–gel silica glasses on their physicochemical properties has been shown and discussed. A lack of influence of the annealing above 1300°C on the lifetimes measured for the nanocrystals embedded in the glass, as compared to the Y₂Si₂O₇:Tb^{3 +} powders, has been observed.     

用两种方法合成长余辉发光玻璃的对比研究

在还原性气氛下高温固相反应法（一步法）合成了长余辉发光玻璃GA；用SrAl2O4:Eu,Dy荧光粉（SAED）与玻璃粉混合高温熔融（二步法）合成了长余辉发光玻璃GB和GC，通过XRD，发光光谱和磷光衰减曲线对样品进行了表征，荧光粉SAED和玻璃GA，GB，GC的发射峰值依次是525，493。462，516nm，发光强度和余辉时间都是SAED＞GC＞GB＞GA，玻璃的发射光谱峰随玻璃组成不同发生位移，两种发生合成的夜光玻璃发光性质存在明显的差异，同一合成方法下，玻璃基料决定着玻璃网络结构，同时也影响着夜光玻璃的发光性质。     

Solid-state optical properties of a chiral supramolecular fluorophore consisting of chiral (1R,2R)-1,2-diphenylethylenediamine and fluorescent carboxylic acid derivatives

By using (1R,2R)-1,2-diphenylethylenediamine as a chiral molecule and 2-anthracenecarboxylic acid as a fluorescent molecule, we created a chiral supramolecular organic fluorophore having circularly polarized luminescence properties in the solid-state.