新型红色荧光粉Sr3Al2O6的合成和发光性能研究

稀土金属离子激活的多铝酸盐发光材料，在可见光区具有较高的量子效率犤１～４犦，充分显示出这类荧光发光材料，在高效节能、环保、电光源与新一代可见光显示器领域的应用前景犤４～９犦。特别是SrAl２O４∶Eu２＋的持续发光现象的发现犤２，３犦，激起了对以稀土金属离子为激活剂，碱土铝酸盐为基质的长余辉无机发光材料体系的兴趣。研究表明其发光强度和余辉时间是传统硫化物发光材料的十倍以上，利用其长余辉储光－发光特性，有望开发新型发光油漆、涂料、发光陶瓷、发光塑料、薄膜、发光纸、发光纤维犤４犦。早在七十年代，荷兰菲利…     

固溶体结构对Ca_(2-x)Sr_xZn_4Ti_(15)O_(36)∶Pr~(3+)发光性质的影响

0引言在绿色和蓝色长余辉发光材料达到应用程度之后,耐候性红色长余辉发光材料成为人们研究的重点。Eu3 、Sm3 激活的硫氧化物[1￣3]、Eu2 铝锶复合硫氧化物[4]和Y2O3∶Eu3 [5]等耐热耐水性红色长余辉材料被相继发现。Pr3 离子掺杂的碱土金属钛酸盐(M TiO3∶Pr,M=M g,Ca,Sr,Ba)是一种新型的红色长余辉发光材料。这种发光材料在615nm附近有很好的单色性红光发射。碱土金属钛酸盐基质化学性能稳定,已开始应用于场发射显示器(FE D)[6,7]。碱土金属钛酸盐是A BO3型化合物,具有钙钛矿结构。B all[8]曾通过在CaTiO3中掺入不同量的Sr2 …     

(CaO)20.68(MgO)1.32(SiO2)4S2∶Eu2+,Dy3+红光材料的制备与发光特性

研究了峰值波长651nm的红色发光材料(CaO)20.68(MgO)1.32(SiO2)4S2∶Eu2 ,Dy3 的制备及发光特性。通过XRD分析表明硫气氛中合成的材料为具有硫成分的硅酸盐相。红光发射带为硫元素进入晶格后在发光中心周围形成了类似长余辉材料CaS∶Eu2 ,Cl-的局域结构。这也使材料具有了硫化物长余辉材料的发射光谱特征和硅酸盐材料高化学稳定性和高亮度的优点。热释光测量揭示它可能是一种潜在的红色长余辉材料。     

Y2O2S∶Eu,Mg,Ti,Tb红色长时发光材料的研究

利用高温固相反应法合成了一种新型的红色长时发光材料--Y2O2S∶Eu, Mg, Ti, Tb. 材料的XRD测试结果表明Eu掺杂引起Y2O2S∶Eu, Mg, Ti, Tb晶胞增大. 激发光谱、发射光谱和发光衰减曲线表明该材料是一种适合紫外线和可见光激发, 并具有很好的长时发光性能的红色长时发光材料. 热释光谱测试结果表明该材料可能具有两个较深的陷阱能级. 研究了Eu, Mg, Ti, Tb的加入量对材料发光特性的影响, 结果表明: Eu, Mg, Ti, Tb影响材料的初始亮度和发光时间, Eu决定材料的红色比.     

Er~(3 ),Ho~(3 )和Tm~(3 )在硫氧化钆中的余辉发光

非放射性长余辉磷光粉作为美化和清洁光源在发光陶瓷、交通安全标志、紧急突发事件的照明设施、工艺美术涂料等众多领域得到越来越广泛的应用,引起人们的重视.到目前为止,文献报道的稀土长余辉磷光体的激活离子主要有铕离子(Eu3+和Eu2+[1-4]、三价铈离子(Ce3+)[5]、三价铽离子(Tb3+)[6]、三价镨离子(Pr3+)[7]、三价钐离子(Sm3+)[8].Ho3+,Er3+,Tm3+等稀土离子作为红外上转换发光材料的激活离子[9～12],而关于它们的长余辉发光的报道极少.最近,雷炳富等在Tm3+离子[13]激活的硫氧化钇体系中发现了长余辉发光.在此,我们通过高温固相法合成了Er3+,Ho3+和Tm3+掺杂的硫氧化钆长余辉磷光粉,观察到该体系中迄今未见文献报道的Er3+,Ho3+和Tm3+离子的长余辉发光.     

喷雾热解法制备球形SrAl_2O_4:Eu,Dy长余辉发光材料

采用喷雾热解两段法制备了SrAl2O4:Eu,Dy长余辉发光材料,利用SEM、荧光长余辉亮度测试、F-4500荧光分光光度等方法分析了不同制备工艺条件下SrAl2O4:Eu,Dy发光材料的形貌、余辉性能以及光谱性能的变化。采用喷雾热解两段法可制备出余辉性能良好的球形SrAl2O4:Eu,Dy长余辉发光材料。前驱体溶液浓度、热解温度、添加剂对产物的形貌、粒度分布、发光性能有较大影响。较之高温固相法,喷雾热解法制备的SrAl2O4:Eu,Dy具有合成温度低、发光性能好、形貌好、粒度分布窄等优点。     

溶剂热合成纳米球状La2O2S:Eu3+荧光粉

Eu3+离子激活的硫氧化物荧光粉是目前国内外广泛使用的CRT红色发光材料[1]. 它具有色纯度高、色彩不失真、亮度-电流饱和度特性好和稳定性高等特性, 已成为CRT不可替代的红色荧光粉. 此外, 掺杂或不掺杂Eu3+的硫氧化镧是还原SO2有害气体为S单质的优良催化剂[2,3]. 近年来兴起的纳米材料是有可能在本世纪得到广泛应用的材料; 掺杂稀土离子的硫氧化物有望应用于各种显示技术及催化剂中. 最近, 吴长峰等[4]在Y2O3∶Eu3+纳米管中观察到发射峰展宽等特性. 因而, 研究Eu3+离子激活的硫氧化镧纳米荧光粉是很有意义的.     

Y2O2S∶Eu,Ti,Mg红色长余辉的温度依赖

实际应用中在低温下一些长余辉材料不能正常工作, 因此需要研究长余辉材料的温度依赖特性. 用固相反应法合成了Y2O2S∶Eu, Ti, Mg, 测量了其余辉发射谱和热释光曲线, 研究Y2O2S∶Eu, Ti, Mg在140～300 K和290～350 K温区的长余辉发光的发射光谱和衰减曲线的温度依赖. 当温度低于其热释光曲线起始点230 K时, 其余辉的发射光谱强度较弱. 随温度增加, 其余辉的发射光谱强度随温度增强. 300 K后, 其余辉衰减时间随温度变快. Y2O2S∶Eu, Ti, Mg长余辉的温度依赖行为与其热释光曲线密切相关, 并通过长余辉机制对其进行了分析和讨论.     

稀土红色长余辉发光材料研究进展

综述了稀土元素掺杂红色长余辉发光材料的研究进展，总结了硫化物、钛酸盐、硫氧化物、硅酸盐、氧化物和磷酸盐等基质体系的红色长余辉发光，并指出硫氧化物和磷酸盐等基质是最具有发展前景的红色长余辉发光体系，讨论了Eu^2 在硫化物、Pr^3 在钛酸盐以及Eu^3 和Sm^3 等稀土离子在硫氧化物和硅酸盐等体系中的红色长余辉发光机制。介绍了传统的高温固相法以及溶胶．凝胶法、微波合成法等稀土红色长余辉材料的制备技术。提出了从基质材料、制备技术和稀土离子发光机制入手是稀土红色长余辉发光材料今后研究与开发的发展方向。     

Eu3+在Ba2TiSi2O8中的发光

红色荧光材料主要有(碱土)硫化物体系[1,2],(碱土)钛酸盐体系[3,4],氧化稀土体系[5],硅酸盐体系[6]以及其它氧化物体系如MO∶Eu~(3 )(M=Ca、Sr、Ba)[7],SrAl2O4∶Eu~(2 )[8]等。在这些体系中,主要以Eu3 做激活     

Sc2MgGa2 and Y2MgGa2

Scandium magnesium gallide, Sc₂MgGa₂, and yttrium magnesium gallide, Y₂MgGa₂, were synthesized from the corresponding elements by heating under an argon atmosphere in an induction furnace. These intermetallic compounds crystallize in the tetragonal Mo₂FeB₂‐type structure. All three crystallographically unique atoms occupy special positions and the site symmetries of (Sc/Y, Ga) and Mg are m2m and 4/m, respectively. The coordinations around Sc/Y, Mg and Ga are pentagonal (Sc/Y), tetragonal (Mg) and triangular (Ga) prisms, with four (Mg) or three (Ga) additional capping atoms leading to the coordination numbers [10], [8+4] and [6+3], respectively. The crystal structure of Sc₂MgGa₂ was determined from single‐crystal diffraction intensities and the isostructural Y₂MgGa₂ was identified from powder diffraction data.     

Zur Kenntnis der Dialkalimetalldichalkogenide β-Na2S2, K2S2, α-Rb2S2, β-Rb2S2, K2Se2, Rb2Se2, α-K2Te2, β-K2Te2 und Rb2Te2

On Dialkali Metal Dichalcogenides β-Na₂S₂, K₂S₂, α-Rb₂S₂, β-Rb₂S₂, K₂Se₂, Rb₂Se₂, α-K₂Te₂, β-K₂Te₂ and Rb₂Te₂ The first presentation of pure samples of α- and β-Rb₂S₂, α- and β-K₂Te₂, and Rb₂Te₂ is described. Using single crystals of K₂S₂ and K₂Se₂, received by ammonothermal synthesis, the structure of the Na₂O₂ type and by using single crystals of β-Na₂S₂ and β-K₂Te₂ the Li₂O₂ type structure will be refined. By combined investigations with temperature-dependent Guinier-, neutron diffraction-, thermal analysis, and Raman-spectroscopy the nature of the monotropic phase transition from the Na₂O₂ type to the Li₂O₂ type will be explained by means of the examples α-/β-Na₂S₂ and α-/β-K₂Te₂. A further case of dimorphic condition as well as the monotropic phase transition of α- and β-Rb₂S₂ is presented. The existing areas of the structure fields of the dialkali metal dichalcogenides are limited by the model of the polar covalence.     

Crystal Structures of [Bu2Sn(O2PPh2)2], [Ph2Sn(O2PPh2)2], and [PhClSn(O2PPh2)OMe]2. Raman Spectra of [Ph2Sn(O2PPh2)2] and [PhClSn(O2PPh2)OMe]2

[(n‐Bu)₂Sn(O₂PPh₂)₂] ( 1 ), and [Ph₂Sn(O₂PPh₂)₂] ( 2 ) have been synthesized by the reactions of R₂SnCl₂ (R=n‐Bu, Ph) with HO₂PPh₂ in Methanol. From the reaction of Ph₂SnCl₂ with diphenylphosphinic acid a third product [PhClSn(O₂PPh₂)OMe]₂ ( 3 ) could be isolated. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P2₁/c with a = 1303.7(1) pm, b = 2286.9(2) pm, c = 1063.1(1) pm, β = 94.383(6)°, and Z = 4. 2 crystallizes triclinic in the space group , the cell parameters being a = 1293.2(2) pm, b = 1478.5(4) pm, c = 1507.2(3) pm, α = 98.86(3)°, β = 109.63(2)°, γ = 114.88(2)°, and Z = 2. Both compounds form arrays of eight‐membered rings (SnOPO)₂ linked at the tin atoms to form chains of infinite length. The dimer 3 consists of a like ring, in which the tin atoms are bridged by methoxo groups. It crystallizes triclinic in space group with a = 946.4(1) pm, b = 963.7(1) pm, c = 1174.2(1) pm, α = 82.495(6)°, β = 66.451(6)°, γ = 74.922(6)°, and Z = 1 for the dimer. The Raman spectra of 2 and 3 are given and discussed.     

Thermal decomposition of Me3SnO2PCl2, Me2Sn(O2PCl2)2 and Ph3SnO2PCl2

TG and DTA studies on Me₃SnO₂PCl₂, Me₂Sn(O₂PCl₂)₂ and Ph₃SnO₂PCl₂ were carried out under dynamic argon atmosphere. The results show that the decomposition proceeds in different stages leading to the formation of Sn₃(PO₄)₂ as a stable product. This compound was characterized by IR spectroscopy. Decomposition schemes involving reductive elimination reactions were proposed.     

The alkali hypophosphites KH2PO2, RbH2PO2 and CsH2PO2

The structures of the hypophosphites KH₂PO₂ (potassium hypophosphite), RbH₂PO₂ (rubidium hypophosphite) and CsH₂PO₂ (caesium hypophosphite) have been determined by single‐crystal X‐ray diffraction. The structures consist of layers of alkali cations and hypophosphite anions, with the latter bridging four cations within the same layer. The Rb and Cs hypophosphites are isomorphous.     

Electrochemical study of (NEt4)2Cl2FeS2MoS2 and (NEt4)2Cl2FeS2MoS2FeCl2

Summary The ability of [MoS₄]^2–, anions to be used as ligands for transition metal ions has been widely demonstrated, especially with Fe²⁺. The present study has been restricted to linear complexes such as (NEt₄)₂ [Cl₂FeS₂MoS₂] and (NEt₄)₂[Cl₂FeS₂MoS₂FeCl₂]. Their electrochemical properties are described: upon electrochemical reduction, these compounds yield MoS₂, as a black precipitate, and an iron complex in solution, assumed to be [SFeCl₂]^2–. The electrochemical reduction goes through two electron transfers, coupled with the breakdown of the molecular skeleton: a DISPl and an ECE mechanism. Depending on the solvent, the following equilibrium may be observed: [Cl₄Fe₂MoS₄]^2–[Cl₂FeMoS₄]^2–+FeCl₂. The equilibrium constant, K_D, was evaluated by differential pulse polarography. K_D is tightly related to the donor number of the solvent.     

Formal [(2+2)+2] and [(2+2)+(2+2)] nonconjugated dienediyne cascade cycloadditions

[reaction: see text] Fluoranthene 2 and heptacycle 3 are easily accessible from the reaction of diyne 1 and norbornadiene (NBD) in the presence of the rhodium catalyst. The unusual [(2+2)+(2+2)] adduct 3 was confirmed by the X-ray crystal structure analysis.