稀土离子RE(RE=Pr,Nd,Eu)在Sr_2CeO_4基质中的发光性质

通过燃烧法合成了Sr2CeO4∶RE材料,研究了Sr2CeO4材料的结晶过程和发光性质及Pr3+,Nd3+和Eu3+稀土离子在Sr2CeO4基质中的发光性能。实验通过燃烧法制得的前驱体在1200℃焙烧2h可得均一的Sr2CeO4相,较传统方法的合成时间大为降低。稀土离子Pr3+,Nd3+和Eu3+的在基质中的少量掺杂(0.02%)均可使Sr2CeO4在475nm左右的特征发射谱峰明显变宽增强,且Eu3+离子的掺杂可使材料在510nm,540nm,610nm左右产生多个明显的稀土离子的特征发射峰。实验合成的发光材料具有良好的发光性能,证明Sr2CeO4材料可作为一种优良的发光材料的基质使用,为寻找新型的发光材料提供了一条新的途径。     

发光颜色可调谐的新型荧光体Sr2CeO4：RE^3＋（RE=Eu，Sm，Dy）的发光性能

Sr2CeO4既是一种有重要应用价值的新型蓝色荧光体，又是一种适合稀土掺杂的发光基质。近年来人们对稀土掺杂的Sr2CeO4的荧光性能进行了研究。本文结合作者的工作，分析了Sr2CeO4的结构特点和光谱特性：综述了Eu^3＋，Sm^3＋，Dy^3＋等稀土离子掺杂Sr2CeO4的发光性能的研究现状，并对今后的研究工作提出了一些设想。     

基质组成对xSrO·yAl2O3：Eu^2＋，Dy^3＋发光性能的影响

研究了基质组成对xSrO·yAl2O3：Eu^2＋，Dy^3＋体系长余辉发光性能的影响，并对其影响机理进行了探讨。XRD分析和长余辉发光性能表明：改变Al2O3／SrO比率可以获得长余辉发光性能较好的3种基质相：SrAl2O4：Eu^2＋，Dy^3＋和Sr4Al14O25：Eu^2＋，Dy^3＋及SrAl4O7：Eu^2＋，Dy^3＋。激发与发射光谱性能分析和余辉衰减特性分析结果表明：随着基质中Sr／Al比例的减小，激发光谱向短波方向延伸，发射峰蓝移，初始余辉亮度越高，余辉持续时间越长。热释光谱分析表明：贫锶相晶格中的陷阱深度与密度较大，因而显示出较好的长余辉发光性能。     

溶液燃烧法与Sol-Gel法制备BAM荧光粉的光谱特性对比分析

在空气中分别采用Sol—Gel法和溶液燃烧法制备了稀土Eu激活的BaMgAl10O17（BAM）荧光粉，并对其光谱特性进行了对比分析。结果表明，Sol—Gel法制备的BAM的荧光光谱与＋3价Eu离子的光谱特征完全相符，为红光发射，其发射主峰位于617nm，属于占据非对称中心格位Eu^3＋的^5Do→^7F2的电偶极（ED）特征发射，而且由于晶场的作用使多重态的^7FJ分裂为多个stark能级，导致^5Do→^7F1、^5Do→^7F3的发射峰裂分为多重峰；而溶液燃烧法制备的BAM的发光呈Eu^2＋离子的特征发射，为典型的蓝色发光，其发射光谱是一个最大峰值位于450nm的宽带谱，归属于Eu^2＋离子的4f^65d→4f^7（^8S7／2）宽带允许跃迁。     

CaAl2O4：Eu^2＋，Nd^3＋纳米粉体的合成与表征

采用溶胶一凝胶法制备了CaAl2O4：Eu^2＋，Nd^3＋纳米粉体发光材料。样品的XRD和SEM分析结果表明：800℃已形成CaAl2O4晶相；样品颗粒尺寸随灼烧温度升高而增加，平均粒径约为20nm～40nm。光谱分析表明：样品的激发光谱为240nm～400nm的宽带谱，在256．6nm和330．6nm处有激发峰。发光光谱是386nm～500nm的宽带谱，峰值位于440nm，与CaAl2O4：Eu^2＋，Nd^3＋粗晶材料相比，光谱发生了“蓝移”现象。样品的热释光峰值位于206℃，与粗晶材料相比，峰值向高温移动了96℃，热释发光峰曲线形状也变宽。样品的发光衰减是由初始的快衰减和随后的慢衰减构成，余辉时间为5h。     

Sr_2Al_(14)O_(25):Eu~(2+),Dy~(3+)的共沉淀-水热合成及其发光性能

以氨水或碳酸铵为沉淀剂,采用共沉淀-水热合成法制备稀土掺杂铝酸锶发光纳米材料,并优化制备稀土掺杂铝酸锶发光材料的工艺条件。对激活剂、助激活剂、助熔剂的用量、体系的酸碱度和灼烧温度对目标产物发光性能的影响规律进行研究。结果表明:目标产物Sr2Al14O25:Eu2+,Dy3+属正交晶系,为蓝绿色长余辉纳米材料,主激发峰均在360 nm左右;氨水共沉淀法制备的产物主发射峰在490 nm,磷光衰减寿命约30 s;碳酸铵沉淀法制备的产物主发射峰在460 nm,磷光衰减寿命约15 s。     

SrAl2O4：Eu^2＋，Dy^3＋长余辉光致发光材料的固相反应法合成与特性

采用高温固相反应法，在还原气氛下制备了掺稀土离子Eu^2 和Dy^3 的铝酸锶长余辉光致发光材料。XRD研究表明，所制备的铝酸盐具备SrAl2O4的晶体结构。SrAl2O4：Eu^2 ，Dy^3 发光材料的发光光谱是中心位于520nm的带状谱，激发峰波长范围位于300nm～500nm，发光余辉可持续12h以上。研究了SrAl2O4：Eu^2 ，Dy^3 发光材料的耐温性和耐水性，结果表明，随热处理温度升高，发光亮度下降；水浸使发光材料与水反应生成水化物，使发光性能下降。     

CaS：Eu，Sm的微波合成与发光性能研究

采用微波合成法快速合成了红外光激励发光材料CaS：Eu，Sm。研究了输出功率对样品发光性能的影响，Eu，Sm双掺杂离子的不同掺杂浓度对发光性能的影响（确定了最佳掺杂浓度），不同助熔剂对发光性能的影响。XRD测试结果表明，CaS：Eu，Sm样品为面心立方结构；SEM照片显示样品粒径在400～500nm范围内；光谱分析表明，样品的红外光激励发光响应范围位于800-1600nm，上转换发光峰值位于655nm，对应于Eu^2＋离子4f^65d→4f^7（^8S7/2）跃迁。     

BaMgSi_2O_6:RE~(3+)(RE=Tb,Ce)的真空紫外光谱特性

研究了MMgSi_2O_6:Tb~(3+) (M=Ca, Sr, Ba)样品的结构、发光特性.MMgSi_2O_6:Tb~(3+) (M=Ca,Sr , Ba)具有硅酸钙镁石结构,基质掺入铽离子后结构没有明显变化.结果表明:MMgSi_2O_6:Tb~(3+) (M=Ca, Sr ,Ba)在168、220和294 nm附近有强烈的吸收峰.在168 nm真空紫外激发下,546 nm是主发射峰.当材料BaMgSi_2O_6:Tb~(3+)中掺杂Ce~(3+)时,BaMgSi_2O_6:Tb~(3+)样品在168 nm真空紫外激发下的发射强度明显下降.     

溶胶-凝胶法制备Eu掺杂Sr_2MgSi_2O_7光致发光性能

采用溶胶-凝胶(sol-gel)法制备稀土离子Eu掺杂的Sr2MgSi2O7硅酸盐基发光材料,通过X射线衍射仪(XRD)、透射电子显微镜(TEM)、荧光分光光度计(PL)对样品的晶体结构、形貌及光学性能进行测试。XRD测试结果表明,在较低的处理温度下可获得Sr2MgSi2O7,但样品中也存在其它的杂质相。荧光光谱测试结果表明,经空气中处理的Eu3+在395 nm光激发下产生590 nm、610 nm的发射峰,通过氢气还原处理后得到的Eu2+离子的发光从250到400 nm的紫外区可以激发峰值为460 nm左右的宽谱带,且随氢气还原温度的升高和Eu离子掺杂浓度的提高发光强度也增强。     

Acid-base behavior of cryptand 1, 4, 7, 10, 13, 16, 21, 24-octaaza-bicyclo [8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hexone and complex formation

The bicyclic cryptand I, 4, 7, 10, 13, 16, 21,24-octaaza-bigcyclo [8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hex-one (COBH) bearing diaminoethane groups along the eight-atom bridges was synthesized. The structure consists of discrete neutral macrobicyclic units; the two cycles share the two tertiary amine nitrogen atoms, which exhibit an endo-endo conformation. Three identical branches formed by I, 2-diaminoethane link the two tertiary amine groups. The protonation reactions ofcryptand (COBH) and its complex formation with copper (II) were investigated by potentiometry in water and in a DMSO/water (80: 20 in mass ratio) mixture as solvents. The cryptand acts as a bis-base through its two Nbridgehead and exhibits a strong cooperativity that favors the first protonation and makes the second one difficult (ΔpK≈5.0 ). An inward rotation of the amide groups to form hydrogen bonds accounts for this cooperativity. The interaction of COBH with copper (II) leads to several binuclear complex proton contents.     

Acid-base behavior of cryptand 1, 4, 7, 10, 13, 16, 21, 24-octaaza-bicycio[8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hexone and complex formation

The bicyclic cryptand 1,4, 7, 10, 13, 16, 21, 24-octaaza-bigcyclo [8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hexone (COBH) bearing diaminoethane groups along the eight-atom bridges was synthesized. The structure consists of discrete neutral macrobicyclic units; the two cycles share the two tertiary amine nitrogen atoms, which exhibit an endo-endo conformation. Three identical branches formed by 1, 2-diaminoethane link the two tertiary amine groups. The protonation reactions ofcryptand (COBH) and its complex formation with copper (Ⅱ) were investigated by potentiometry in water and in a DMSO/water (80: 20 in mass ratio) mixture as solvents. The cryptand acts as a bis-base through its two Nbridgehead and exhibits a strong cooperativity that favors the first protonation and makes the second one difficult (pK 5.0 ). An inward rotation of the amide groups to form hydrogen bonds accounts for this cooperativity. The interaction of COBH with copper (Ⅱ) leads to several binuclear complex proton contents.     

Supplemental Literature Review of Binary Phase Diagrams: Cs-In, Cs-K, Cs-Rb, Eu-In, Ho-Mn, K-Rb, Li-Mg, Mg-Nd, Mg-Zn, Mn-Sm, O-Sb, and Si-Sr

Recent literature on Cs-In, Cs-K, Cs-Rb, Eu-In, Ho-Mn, K-Rb, Li-Mg, Mg-Nd, Mg-Zn, Mn-Sm, O-Sb, and Si-Sr phase diagrams is reviewed in this article in order to update the 1990 compilation Binary Alloy Phase Diagrams, 2nd edition, by T.B. Massalski, et al. For some systems reaction tables and crystal structure data have been included, as well. Diagrams have been checked for consistency with rules for phase diagram construction and modified when necessary. In addition, diagrams needing more work have been identified.     

Supplemental Literature Review of Binary Phase Diagrams: Bi-Ce, Bi-Er, C-Ce, C-La, C-Pr, Cd-I, Cr-Cu, Cu-Er, Er-Sb, F-Sm, F-Yb, and Fe-Gd

Recent literature on Bi-Ce, Bi-Er, C-Ce, C-La, C-Pr, Cd-I, Cr-Cu, Cu-Er, Er-Sb, F-Sm, F-Yb, and Fe-Gd phase diagrams is reviewed in this article in order to update the 1990 compilation Binary Alloy Phase Diagrams, 2nd edition, by T.B. Massalski, et al. For some systems reaction tables and crystal structure data have been included, as well. Diagrams have been checked for consistency with rules for phase diagram construction and modified when necessary. In addition, diagrams needing more work have been identified.