Spectral Structures of Eu~(2 ) in ABF_4 and A_2SiF_6 (A=Na,K,Rb,Cs)

The phosphors of ABF_4:Eu~(2 )and A_2SiF_6:Eu~(2 )(A=Na,K,Rb,Cs)have been synthesized,and thecrystallographic data obtained accord with ASTM.In these materials,the f→f sharp lines emissions of Eu~(2 )were observed.The coordination numbers of Eu~(2 )in both NaBF_4 and Na_2SiF_6 hosts are less than 8.     

Fluorescence of Sm~(2+) and Eu~(2+)→Sm~(2+) Energy Transfer in SrB_4O_7

Fluorescence spectra of Sm~(2+)and Eu~(2+)→Sm~(2+)energy transfer were studied in SrB_4O_7.There appearsonly fluorescence from ~5D_0 transition of Sm~2+ at 77 K.The vibronic lines associated with ~5D_0→~7F_0 transitionwere observed.The thermal population to upper states of ~5D_1 and 4f~5d levels from ~5D_0 gives rise to ~5D_1→~7F_J and 5d→4f radiative transitions of Sin~(2+)at higher temperature.     

LUMINESCENCE CENTERS OF Eu~(2 ) IN KCaF_3:Eu~(2 )

The nature of the emission center of Eu~(2 ) in KCaF_3:Eu~(2 ) strongly depends on the preparative condi-tions.Experimental results show that there are two different d→f transition emission bands,and the origin ofthese two emission bands,their interrelationship and the effect of doping concentration on them have been dis-cussed.A Eu~(2 )-Eu~(3 ) valency change process has been proposed.     

SrAl_2O_4∶Eu~(2+),Nd~(3+) and Dy~(3+) Long Afterglow Phosphor

Longafterglowphosphorabsorbingenergyfromsolar,lampandotherlightsourcesforashorttimestorestheenergyandexhibitsbrightandlong lastingphosphorescencewhichsuitsthevisualperceptionofthehumaneyewithminimumbrightness 0 32mcd·m- 2 andlastingtimemorethan 8h) .TheSrAl2 O4 ∶Eu2 +,Dy3+phosphorhasbeenknowntobeagreenlongafterglowphosphorwithanemissionpeakat 5 2 0nm[1～ 7] .ThepropertiesofthephosphorwerefurtherexaminedbythegroupofTangMingdaoandMatsuzawaTindetailin 1995and 1996respectively[1,2 ] .Inorde…     

新型蓝色长余辉荧光粉SrAl_2O_(4-y)N_y∶Eu~(2+),Dy~(3+)发光性能研究

采用高温固相反应合成了SrAl_2O_(4-y)N_y∶Eu~(2+),Dy~(3+)系列长余辉荧光粉,并研究了SrAl_2O_(3.75)N_(0.25)∶Eu~(2+),Dy~(3+)体系的晶体结构、光谱特性、余辉衰减曲线及热释发光曲线。X射线衍射分析结果表明,SrAl_2O_(3.75)N_(0.25)∶Eu~(2+)荧光材料属六方晶系,P6322空间群,晶胞参数a=b=5.14,c=8.462,γ=120°。荧光光谱测试结果表明,SrAl_2O_(3.75)N_(0.25)∶Eu~(2+)的激发光谱和发射光谱均为宽带谱,激发光谱位于283 nm~450 nm,发射光谱的峰值位于487 nm,属于Eu~(2+)的4f65d1→4f7跃迁发射。Eu~(2+)的掺杂量并不改变SrAl_2O_(3.75)N_(0.25)∶Eu~(2+)发射光谱的形状和峰值位置,但对相对发光强度有较大影响,Eu~(2+)的摩尔浓度为2%时相对发光强度最高。余辉衰减曲线表明,Sr_(0.97)Al_2O_(3.75)N_(0.25)∶Eu_(0.02),Dy_(0.01)的余辉衰减符合指数衰减规律,由初始的快衰减和之后的慢衰减两个过程组成。通过热释发光曲线对荧光材料中的陷阱能级进行计算,得出Sr_(0.97)Al_2O_(3.75)N_(0.25)∶Eu_(0.02),Dy_(0.01)的能级陷阱为0.42 V,掺Dy~(3+)有利于提高该荧光材料的初始发光亮度和余辉时间。     

VUV Spectroscopy of GdPO_4∶Eu~(3 ) and GdBO_3∶Eu~(3 )

VUV Spectroscopy of GdPO_4∶Eu~(3 ) and GdBO_3∶Eu~(3 )@Zimmerer G$Institut für Experimentalphysik der Universitt Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany     

Emission Spectra and Crystallographic Sites of Eu~(2+) in Ca_8Zn(SiO_4)_4Cl_2

The fluorescent characteristic and emission spectra of Eu~(2+) in the cubic structureCa_8Zn(SiO_4)_4Cl_2 with three kinds of cation sites is reported.The influence of temperature,Eu~(2+) concentra-tion and excitation conditions on fluorescent properties of Eu~(2+) are studied at 77 and 298 K.Thecoordination number of Eu~(2+) at different sites is obtained.The green and red emission bands arise fromEu_(2+) ions locating on eight- and six- coordinated inequivalent sites respectively.     

固体中4f~6(Eu~(3 ))构型晶场计算的平截效应

固体中4f(Eu~(3~4))构型的晶场(C.F),通常是根据7F 七重线中的49相似文献   

Luminescent Properties of BaMgAl_(10)O_(17)∶Eu~(2+) Phosphors Coated with Y_2SiO_5

BaMgAl_(10)O_(17)∶Eu~(2+)(BAM)is the blue compo-nent of the rare earth tricolor phosphor,and it hasbeen widely applied in tricolor fluorescent lamps duetoits highluminescent efficiency.However,deteriora-tion of this phosphor[1~5]li mits the lifeti me of thelamps.The deterioration of the brightness has twoforms:thermal deterioration and deterioration in igni-tion.Thermal deterioration mainly happens inthe pro-cess of lamp production.In general,it is consideredthat this deterioration comes f…     

柠檬酸盐溶胶凝胶法合成Li_(1 2x)Zn_(1-x)PO_4及其离子导电性

采用柠檬酸盐溶胶 凝胶法制备了组成为Li1 2xZn1-xPO4 (x =0 ,0 .1,0 .14,0 .2 ,0 .3,0 .4,0 .5 )的固体粉末和烧结体。对其结构的研究结果表明 ,在这样的组成范围内 ,采用溶胶 凝胶法得到了一系列α LiZnPO4 (x =0 )、Li9Zn6(PO4 ) 7(x =0 .14)、α Li4 Zn(PO4 ) 2 (x=0 .5 )单相以及由α LiZnPO4 Li9Zn6(PO4 ) 7、α Li4 Zn(PO4 ) 2 Li9Zn6(PO4 ) 7两相构成的混合相 ,用这种合成方法得到的样品的生成温度较传统的固相合成样品降低了约 40 0℃。用交流阻抗技术测定了样品的导电性 ,其中α LiZnPO4 、Li9Zn6(PO4 ) 7在室温下不显示导电性 ,而α Li4 Zn(PO4 ) 2 具有较高的导电性 ,t=2 5℃时 ,σ=1.6 6× 10 -6S·cm-1。     

Crystal Structure of{[(μ_2-Cl)(C_5H_5)Sm(μ_2-Cl)]_2(μ_3-Cl)(μ_4-O)Sm(μ_2-Cl)·THF}_2~(2-)·[Li(DME)_2·Li(THF)_2·DME]~(2 )·DME

The crystal structure of title complex has been determined by the method of X-ray single crystaldiffraction.The crystal belongs to monoclinic space group C_(2/c)with the unit parameters a=2.8907(7),b=2.0431(5),c=1.5723(3)nm;β=115.67(2)°.The unit volume V is 8.36924(348)nm~3;Z=8,Dc=1,82g·cm~(-3),μ(MoK_α)=46.4cn~(-1); F(000)=4416.The final R is 0.083,Rw 0.088.The title complex con-sists of two univalent cations and one divalent anion.The anion has a cluster structure including six Sm~(3 ).Coordination numbers of all six Sm~(3 )are eight,but their surroundings are different from each other.Two ofthem are decahedral array,and the others are octahedral array f the centroid of each pentacyclodienyl ring istaken as one point.     

Study on Spectra of La_2CaB_(10)O_(19)∶Eu~(3 ) in VUV-VIS Range

Manyboratesareexcellenthostsforrareearthlu minescence ,forexample ,nowbestredphosphorinplasmadisplaypanel (PDP )is (Y1-xGdx)BO3∶Eu[1] .Boratephosphorsdopedwithrareearthionshavebeenrichlystudiedinthepastfewdecades[2 ,3] .RecentlyWuYichengetal .[4 ] synthesizedanewbo rateLa2 CaB10 O19,whichispotentialnonlinearopticalmaterials.InthisworkweselectedLa2 CaB10 O19ashostofluminescencematerialsbecauseitprobablyisabetterhostforrareearthluminescence .Duetotherequirementofplasmadisplaypenal(PDP)…     

Sr_(1-x)Ba_xAl_2O_4∶Eu~(2+)夜光粉的合成与发光性能研究

采用高温固相合成法制备了Sr1-xBaxA2O4:EU2+夜光粉，发现以木炭粉作为还原剂，A12O3与SrCO3的摩尔比为1．85：1,激活剂EU2＋浓度为XEU2＋＝0．05～0．07，反应温度7≥1200℃，灼烧时间3h，并掺人少量H3BO3作助熔剂的条件下，可获得余辉亮度较ZDS型夜光粉好的长余辉发光材料SrA12O4：Eu2+。掺入少量Ba2+取代部分Sr尸+所合成的SY0．8Bao．ZAl2O4：Eu2+同样具有良好的长余辉特性。研究了Sr1-xBaxA2O4:EU2+（X=0．0.0．2）的激发和发射光谱，并对其发光衰减进行了比较和分析。     

Synthesis and Crystal Structure of a Novel Ion-pair Complex of [Li(THF)_4Nd(C_8H_8)_2]·2THF

The reaction of NdCl_3 with lithium methylnaphthalene in 1:2 mole ratio in THF generates black powder.The powder reacts with cyclooctatetraene(COT)in THF to form the title complex.[Li(THF)_4Nd(C_8H_8)_2]·2THF crystallizes in the monoclinic space group P2/c with unit-cell dimensions a=1.7858(7)nm,h=1.3243(4)nm,c=1.8086(6)nm.β=106.52(4)°,V=4.10 nm~3 and D_c=1.268 g/cm~3 for Z=4.F(000)=1660,R=0.0774,R_n=0.0733.The complex consists of discrete ion-pair and two THF moleculesadduct.In the anion,the neodymium atom is coordinated by two COT rings.The structure of the cation showsthat the lithium atom is attached with THF molecules only.     

掺杂离子对红色荧光粉NaLn_4(SiO_4)_3F∶Eu~(3+)(Ln=La,Gd,Y)发光性能的影响

利用高温固相法合成系列Na Ln4(Si O4)3F∶Eu3+(Ln=La,Gd,Y)红色荧光粉,用X射线粉末衍射仪和荧光分光光度计对荧光粉进行结构和性能表征,研究Eu3+浓度以及基质组成的变化对Na Ln4(Si O4)3F∶Eu3+(Ln=La,Gd,Y)发光性能的影响。在394 nm激发下,荧光粉Na La4-x(Si O4)3F∶x Eu3+中的Eu3+主要体现5D0→7F2(616 nm)和5D0→7F1(590 nm)跃迁发射,而且5D0→7F2和5D0→7F1跃迁发射强度比例随Eu3+浓度的增大而变化,较低浓度时5D0→7F1发射比5D0→7F2强,较高浓度时则刚好相反。在273 nm激发下,荧光粉Na La3.9-yGdy(Si O4)3F∶0.1Eu3+或Na La3.9-zYz(Si O4)3F∶0.1Eu3+中Eu3+的5D0→7F2(616 nm)发射随掺杂离子浓度增加而增强,而5D0→7F1发射强度变化不大。因此可以通过改变Eu3+浓度以及基质组成离子Gd3+或Y3+浓度对5D0→7F2和5D0→7F1发射强度加以调整,进而调整荧光粉的红光色度。     

Luminescence and Energy Transfer Properties of Ca_2Gd_8(SiO_4)_6O_2∶A(A=Pb~(2 ), Tm~(3 ))Phosphors

Compoundswiththeapatitestructureareverysuit ablehostlatticesforvariousluminescentions .ThemostwellknownexampleisSb3 andMn2 coactivatedcalci umhalophosphateCa5(PO4 ) 3(F ,Cl)∶Sb ,Mn ,whichhasfoundapplicationsinfluorescentlampsforalongtime[1] .Ca2 R8(SiO4 ) 6 O2 (R =Y ,Gd ,La)isakindofternaryrare earth metalsilicatewiththeoxyapatitestructure ,whichhasbeenusedashostmaterialsfortheluminescenceofvariousrareearthandmercury likeions[2～ 4 ] .Themostprominentstructuralcharacteristicisthetwos…     

Electron Transition of Eu~(2+) and Energy Transfer in Crystals BaFX:Eu~(2+),Eu~(3+) (X=Cl,Br)

In crystals BaFX:Eu~(2+)(X=Cl,Br).there exists configuration interaction between 4f~65d and 4f~65s ex-cited state of Eu~(2+)ion.and it results in the change of relative intensities of d-f and f-f transition.The transition~S_-_2→4f~65d-6s is observed.The variation of F/X atomic ratio between 110/90 and 90/110 does not obvi-ously influence the luminescence of BaFX:Eu~(2-).There is energy transfer between Eu~(2+)(f-f)and Eu~(3+)whichcoexists in the matrices.     

Effect of Eu~(3+) contents on structure and luminescence properties of Na_3Bi_(2–x)(PO_4)_3:xEu~(3+) and Na_3Bi_(1–x)(PO_4)_2:xEu~(3+) phosphors

A series of Na_3Bi_(2–x)(PO_4)_3:xEu~(3+) and Na_3Bi_(1–x)(PO_4)_2:xEu~(3+) phosphors were successfully synthesized by solid-state method.The structure and luminescence properties were carefully investigated.The excitation spectra presented an obvious excitation band,and the peak was located at 396 nm,which matched well with the popular emissions from near-UV light-emitting diode chips.With the phase of Na_3Bi_(2–x)(PO_4)_3:xEu~(3+) changing to that of Na_3Bi_(1–x)(PO_4)_2:xEu~(3+),the intensity of magnetic dipole transition(~5D_0→F_1) at 598 nm became stronger than that of electric dipole transition(~5D_0→~7F_2) at 621 nm.Under 396 nm excitation,the chromaticity coordinates and the decay curves of the entitled phosphors were also investigated.Based on all experiments without concentration quenching,we could control the luminescence intensity of the material by adjusting the doping amount of the active ions.All results indicated that Na_3Bi_(2–x)(PO_4)_3:xEu~(3+) and Na_3Bi_(1–x)(PO_4)_2:xEu~(3+) phosphors have potential application as red phosphors in near UV chip-based white light emitting diodes.     

Eu3+掺杂Sr2CeO4荧光体的制备、发光性能及能量传递

采用柠檬酸-凝胶法成功地制备了Eu3+掺杂的Sr2CeO4荧光体.用X射线粉末衍射、拉曼光谱、紫外可见吸收光谱和荧光光谱等分析手段研究了荧光体的结构、光致发光性能及能量传递.结果表明,Sr2CeO4∶ Eu荧光体的激发光谱由两部分组成一个宽的激发带和属于Eu3+的f - f跃迁的锐线谱(峰位是395nm、466nm、532nm),它的发射光谱中除了出现常见的发射峰如585nm(5D0→7F1) 、616nm(5D0→7F2)、655nm(5D0→7F3)和704nm(5D0→7F4)外,还包含有来自较高能级激发态5D1的跃迁的发射,即509nm(5D1→7F0)、534nm(5D1→7F1)、554nm(5D1→7F2).这些发射峰在其它基质材料中难以观察到.发射主峰位于616nm附近,没有出现5D0→7F0的跃迁发射,这表明Eu3+在Sr2CeO4基质中处于无反演中心或偏离反演中心的格位上.Sr2CeO4∶Eu荧光体中存在着从基质Sr2CeO4到Eu3+的能量传递.     

Luminescence and Preparation of LED Phosphor Ca_8Mg(SiO_4)_4Cl_2∶Eu~(2 )

Eu2 isthemostwell knownandextensivelyused activatorinmanysilicates,boratesandotherinorganic compounds[1～4].Itsemissioncomesfrom5d→4ftran sition,andtheemissionwavelengthcanvaryinvery broadranges.Sincethe5delectronsarelocatedat outershelloftheeuropiumion,…