BaM_2ZnO_5∶Eu~(3+)(M=La,Gd)荧光粉的合成及其光谱研究

为了探索Eu3+在晶格位置中占据不同对称中心时的发光性质,采用高温固相法制备了BaM2ZnO5∶Eu3+(M=La,Gd)系列红色荧光粉,分别用X射线衍射(XRD)、扫描电镜(SEM)、荧光光谱(PL)对其晶体结构、形貌和发光性质进行了表征。结果表明,经1000℃烧结后可得到BaM2ZnO5(M=La,Gd)纯相,荧光粉的颗粒大小分布较均匀,粒径大约为3μm~5μm;BaM2ZnO5∶Eu3+(M=La,Gd)荧光粉可以被395 nm的近紫外光有效激发,BaLa2ZnO5∶Eu3+在595 nm处的发射峰为最强峰,对应于Eu3+的5D0→7F1(595 nm)磁偶极跃迁。Ba Gd2ZnO5∶Eu3+在627 nm处的发射峰为最强峰,对应于Eu3+的5D0→7F2(615 nm,627 nm)电偶极跃迁。     

绿色荧光粉LaPO4∶Ce,Tb的发光性能研究

合成了细颗粒灯用绿色荧光粉;对各稀土离子分别进行光谱和发光性能研究,发现Ce3+、Tb3+、Gd3+离子的浓度对荧光粉的亮度有较大影响;该粉主发射峰是545nm,发光亮度高;颗粒较细且粒度分布均匀,平均粒径为3μm～4μm。     

绿色荧光粉LaPO4∶Ce,Tb的发光性能研究

合成了细颗粒灯用绿色荧光粉; 对各稀土离子分别进行光谱和发光性能研究, 发现Ce3+、Tb3+、Gd3+离子的浓度对荧光粉的亮度有较大影响; 该粉主发射峰是545nm,发光亮度高; 颗粒较细且粒度分布均匀, 平均粒径为3μm～4μm.     

BaAl12O19中Mn2+和Tb3+的发光及Tb3+对Mn2+的能量传递

采用溶胶-凝胶法合成了Mn2+、Tb3+单掺及共掺的BaAl12O19荧光粉,对其发光性质和Tb3+对Mn2+的能量传递机理进行了研究.研究结果表明,Tb3+单掺的BaAl12O19荧光粉,发射峰位于440nm、489nm、543nm、587nm和623nm,属于Tb3+的5D3→7FJ和5D4→7FJ (J=6,5,4,3)跃迁发射;Mn2+单掺的荧光粉,发射峰位于516nm,归属于Mn2+的4T1→6A1跃迁发射.Mn2+,Tb3+共掺后,Mn2+的发射强度明显提高,而Tb3+的发光强度降低,Tb3+对Mn2+有能量传递作用.初步证实Tb3+对Mn2+的能量传递机理为激子能量传递.     

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。     

微波场作用下La2O2S:Tb绿色荧光粉的快速合成及其发光特性

采用微波法快速合成了La2O2STb绿色荧光粉.用X射线粉末衍射(XRD)、扫描电镜(SEM)、荧光分光光度计等对合成产物的结构、形貌以及发光特性进行了研究.结果表明,材料的晶体结构为六方晶系,与La2O2S的相同.颗粒的形貌多为六边形,分散性很好,尺寸在2μm左右.发射光谱由498nm、547nm、590nm、624nm等一系列窄带发射峰组成,归属于Tb3+从5D4到7FJ(J = 0～6)的跃迁.主发射峰位于547nm,对应于5D4→7F5的能级跃迁,导致一种绿光发射.研究发现Tb的掺杂浓度对样品主发射峰的发光强度有着很重要的影响,在7%(摩尔分数)时达到最大,继续增加Tb的浓度,发光强度反而降低.     

Tb~(3+)掺杂ZnWO_4基绿色荧光粉的发光性能

以柠檬酸为螯合剂,采用沉淀法制备了稀土Tb3+掺杂的ZnWO4绿色荧光粉前驱体。通过差热分析(DTA)、热重分析(TG)、X射线衍射(XRD)等手段对产物进行了表征。结果表明,当退火温度低于700℃时,得到的样品为非晶态,而高于850℃退火处理后为单斜结构。使用荧光分光光度计研究了Tb3+在ZnWO4基质中的发光性质。结果显示,ZnWO4:Tb3+样品在544nm波长光的监测下于200~300nm处出现由W→O及Tb→O跃迁共同作用产生的重叠激发峰和系列Tb3+的f-f跃迁锐峰,其中位于488nm处的激发峰非常显著,对应于Tb3+的7F6→5D4跃迁。说明该法制备的荧光粉ZnWO4:Tb3+能够被蓝光有效激发,可以与广泛使用的蓝光LED芯片的输出波长相匹配。在488nm波长光的激发下观察到ZnWO4粉末中Tb3+的544nm(5D4→7F5)强的特征发射,说明ZnWO4:Tb3+粉末可作为白光LED的绿色补偿荧光粉。当以267nm激发ZnWO4:Tb3+时,有宽的WO2-4特征发射峰和Tb3+的5D4→7F6及5D4→7F5跃迁产生的发射峰,随着Tb3+掺杂浓度的增加,WO2-4的特征发射强度逐渐降低,而Tb3+的5D4→7F5跃迁强度增大,表明Tb3+与WO2-4之间有能量转移。     

稀土-对叔丁基杯[8]芳烃二甲亚砜配合物的合成和荧光性能研究

在丙酮溶液中,RE(ClO4)3·(DMSO)n(RE=La,Sm,Gd,Tb,Dy)与对叔丁基杯[8]芳烃(H8L=C88H112O8)反应,合成了5种新的稀土固体配合物,通过元素分析、红外光谱、紫外光谱和摩尔电导等实验进行了表征,确定了配合物组成为[RE2(H2L)(DMSO)5](RE=La,Sm,Gd,Tb,Dy),在常温下研究了它们的固态粉末荧光光谱,结果发现,铽-对叔丁基杯[8]芳烃配合物具有较好的发光性能。     

稀土-对叔丁基杯[8]芳烃-N,N-二甲基甲酰胺配合物的合成、表征及铽的光致发光

在N,N-二甲基甲酰胺(DMF)溶液中,对叔丁基杯[8]芳烃(H8L=C88H112O8)与RE(NO3)3·4DMSO(RE=La,Sm,Gd,Tb,Dy)反应,合成了5种新的稀土固体配合物,通过元素分析、红外光谱和热谱等实验进行了表征,确定了配合物组成为RE(H6L)(NO3)(DMF)6(RE=La,Sm,Gd,Tb,Dy),在常温下研究了它们的固态粉末荧光光谱,结果发现,铽-对叔丁基杯[8]芳烃配合物具有良好的荧光性能。     

Sr_2MgSi_2O_7∶Eu~(2+),Dy~(3+)发光纳米纤维的制备及表征

采用静电纺丝技术制备了非晶态PVP/[Sr(NO3)2+Mg(NO3)2+TEOS+Eu(NO3)3+Dy(NO3)3]复合纳米纤维,在还原气氛下对其进行煅烧,得到了一维纳米结构的Sr2Mg Si2O7∶Eu2+,Dy3+发光纤维。对其热性能、物相结构、形貌结构及发光性能进行了表征。热分析表明,温度高于800℃时,复合纤维中的水分、有机物、硝酸盐分解挥发完全,样品不再失重;物相分析表明,经1100℃还原气氛焙烧后形成了发育良好的晶相Sr2Mg Si2O7∶Eu2+,Dy3+纳米纤维;形貌分析表明,Sr2Mg Si2O7∶Eu2+,Dy3+发光纳米纤维表面粗糙,平均直径约为350 nm,呈颗粒串珠结构;荧光光谱分析表明,在360 nm的近紫外光激发下,Sr2Mg Si2O7∶Eu2+,Dy3+纳米纤维发射出Eu2+特征的明亮的蓝光,发射峰位于468 nm;余辉衰减曲线表明,Sr2Mg Si2O7∶Eu2+,Dy3+纳米纤维在紫外光照射15 min后其初始余辉亮度达到0.32 cd/m2,肉眼可见。     

Co-Precipitation Synthesis and Spectral Characteristics of Long Afterglow Phosphor Y2O2 S： Sm^3＋, Mg^2＋ , Ti^4＋

Y2O2S：Sm^3＋, Mg^2＋, Ti^4＋ phosphor was synthesized by co-precipitation method. The crystalline structure of all synthesized phosphors was investigated by XRD. The result showed that all synthesized phosphors had a hexagonal crystal structure, which was the same as Y2O2S. The emission spectrum and excitation spectrum were measured, and the effect of Sm^3 ＋ molar ratio on the spectra was discussed. The emission spectra of the phosphors showed three emission peaks due to typical transitions of Sm^3 ＋ （4G5/2→6HJ ,J = 5/2, 7/2, 9/2）, and the emission peaks at 606 nm was stronger than others. With the increase of Sm^3 ＋ molar ratio, the emission intensity was strengthened. The excitation peaks were ascribed to the representative energy transition 4f→4f of Ti^4＋ phosphor prepared by co-precipitation method was Sm^3＋ ions. The results indicated that the Y2O2S ： Sm^3＋ , Mg^2＋ , an efficient long afterglow phosphor.     

Luminescence Properties of Rare Earth Ions in Cadmium Metasilicate

The luminescence properties of CdSiO3:RE^3 phosphors doped with various rare earth ions are reported. The series of rare earth ions doped CdSiO3 phosphors are prepared by the conventional high-temperature solid-state method, and characterized by XRD and photoluminescence (PL) spectra. The results of XRD measurement indicate that the products fired under 1050 ~C for 3 h have a good crystallization without any detectable amount of impure phase. The PL spectra measurement results show that CdSiO3 is a novel self-activated luminescent matrix. When rare earth ions such as Y^3 ,La^3 , Gd^3 , Lu^3 , Ce^3 , Nd^3 , Ho^3 , Er^3 , Tm^3 and Yb^3 are introduced into the CdSiO3 host, one broadband centered at about 420 nm resulted from traps can be observed. In the case of other earth ions which show emissions at the visible spectrum region, such as Pr^3 , Sm^3 , Eu^3 , Tb^3 and Dy3 , the mixture of their characteristic line emissions with the ～420 nm strong broadband luminescence results in various emitting colors. As a consequence, different emitting colors can be attairied via introducing certain appropriate active ions into the CdSiO3 matrix. In additional, this kind of phosphors shows good long-lasting properties when excited by UV light. All the results show that CdSiO3 is a potential luminance matrix.     

Effect of trivalent rare earth ions doping on the fluorescence properties of electron trapping materials SrS：Eu~（2＋）

Trivalent rare-earth ions (La3+,Pr3+,Nd3+,Sm3+,Gd3+,Tb3+,Dy3+,Ho3+,Er3+,Tm3+,and Yb3+) were investigated as the codoped auxiliary sensitizer for the electron trapping materials SrS:Eu2+ in order to enhance the fluorescence properties.It was found that Sm3+ and Tb3+ had the best photoluminescence stimulated luminescence (PSL) effect among the selected trivalent rare-earth ions.All the SrS:Eu2+ samples doped by different trivalent rare-earth ions could be stimulated by 980 nm laser after being exposed to the conventional sunlight,and they emitted PSL with the peak located at 615 nm.The result also indicated that some co-doped rare earth ions could increase fluorescence intensities of the traditional electron trapping materials SrS:Eu2+.     

Fabrication and Luminescence Properties of Ca2Gd8(SiO4)6O2:Er3+ Phosphors via Sol-Gel Process

Ca2RE8(SiO4)6O2 (RE=Y, Gd, La) is a kind of ternary rare-earth-metal silicate with the oxyapatite structure, which was used as host materials for the luminescence of various rare earth and mercury-like ions. Ca2Gd8(SiO4)6O2:Er3 phosphors were prepared through the sol-gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicate that the phosphors crystallized completely at 1000 ℃. SEM study reveals that the average grain size is 400～1000 nm. In Ca2Gd8(SiO4)6O2:Er3 phosphors, the Er3 shows its characteristic green emission at 528 nm (2H11/2-4I15/2) and 548 nm(4S3/2-4I15/2) upon excitation into 382 nm, with an optimum doping concentration of 5% (mole fraction) of Gd3 in the host lattices.     

Photoluminescence characterization and energy transfer of NaBa1-x-yPO4：xCe3＋, yTb3＋ phosphors

A series of NaBa1-x-yPO4: xCe3+, yTb3+ phosphors were synthesized by solid-state reaction method. The crystal structure, photoluminescence emission and excitation spectra and decay times of the phosphors were carefully investigated. The results revealed that an efficient energy transfer occurred from Ce3+ to Tb3+ ions in NaBaPO4 host by means of dipole-dipole interactions and the critical distance of the energy transfer was about 0.638 nm. Moreover, the phosphor emitted strong green emission under UV excitation, indicating that the phosphors are potentially useful as a highly efficient, green-emitting phosphor.     

Vacuum Ultraviolet Spectral Investigations on Green-Emitting Ca(La,Gd)4Si3O13:Tb3+ Phosphors for PDP Applications

In an effort to develop new green-emitting PDP phosphors with high efficiency, investigated were the synthesis, VUV photoluminescence (PL) spectra, optical properties, and chromaticity of Ca(La1-x-yTbxGdy)4Si3O13 phosphors by using synchrotron radiation. Upon analysis of the VUV spectroscopic and chromaticity investigations on the new green-emitting VUV phosphors, were an optimized composition achieved. The PLE spectral studies show that Ca(La1-x-yTbxGdy)4Si3O13 exhibit significant absorption in the VUV range. The VUV PL intensity was found to enhance with Gd3 -doping. Furthermore, the 1931 CIE chromaticity coordinates of Ca(La,Gd)4Si3O13:Tb were found to be (0.286, 0.548), as compared to (0.230, 0.712) for Zn2SiO4:Mn2 as a reference. The potential application of Ca(La,Gd)4Si3O13:Tb as a new green-emitting PDP phosphor are being currently improving and evaluating.     

Photoluminescence of SrGdGa_3O_7∶RE (RE=Ce~(3 ), Pr~(3 ), Tb~(3 )) under VUV-UV Excitation

SrGdGa3 O7belongstothelargefamilieswhosegeneralchemicalformulaisAMM′3 O7(A =Ca ,Sr ,Ba ;M =La ,Gd ,Y ;M′ =Al,Ga) .Thesecom poundshavemelilitestructure .Structuralinvestiga tionsindicatethatSrGdGa3 O7formstetragonalcrystalswithspacegroupP 4 2 1m .Theunit…     

Luminescent properties of blue long-lasting phosphorescence phosphors Sr6Al18Si2O37：Eu2＋,RE3＋

A series of novel blue long-lasting phosphorescence phosphors Sr6A118Si2037：Eu^2＋,RE^3＋ （RE3＋=Ho^3＋, Gd^3＋, Dy^3＋ and Pr^3＋） were prepared by the conventional high-temperature solid-state reaction in a reductive atmosphere. Their properties were systemati- cally investigated utilizing X-ray diffraction （XRD）, photoluminescence, phosphorescence and thermoluminescence （TL） spectra. The phosphors emitted blue light that was related to the emission of E~＋ due to 5d-4f transition. Bright blue long-lasting phosphorescence （LLP） could be observed after the excitation source was switched off. For the optimized sample, the blue long-lasting phosphores- cence could last for nearly 4 h in the light perception of the dark-adapted human eye （0.32 mcd/m2）. The effects of RE3＋ ions on phosphorescence properties of the phosphors were studied, and the results showed that the co-doping of RE^3＋ ions greatly enhanced the intensity of the peak around 315 K which was related to the long lasting phosphorescence of the phosphors at room temperature and consequently improved the performance of the blue phosphorescence such as intensity and persistent time.     

Synthesis, Characterization and Fluorescence of Rare earth Nitrate Complexes with Triaza-crown Ether Derivative

Sinceaza crownethershowsspecialcoordinationpropertiestotransitionmetalandheavymetalions[1,2 ] ,therearemanyreportsofthecomplexesinhost guestchemistry ,molecularrecognition[3 ,4] andionophoreinmembranetransportation[5] ,butthereislittlereportontheirrareearthscomplexesandthefluorescenceaboutthecomplexes[6] ,andthefluorescenceintensityoftheircomplexesarenotverystrong .Weinsetbenzoylgroupintothemacrocycle ,expectingthatitsrareearthscomplexeshavebetterfluorescenceproperties .Inthispaperthesynthesis…     

Synthesis, Characterization and Fluorescence Properties of Europium, Terbium Complexes with Biphenyl-4-Carboxylic Acid and o-Phenanthroline

Two series of solid complexes of europium and terbium with biphenyl 4-carboxylic acid and phen were synthesized and characterized in this report. Their elemental analysis, molar conductivities and TG-DTA studies indicate that the complexes have the composition of Eu(phen)L3·1/2H2O, Eu0.5RE0.5(phen)L3·1/2H2O; Tb(phen)L3·H2O and Tb0.5RE0.5(Phen)L3·1/2H2O. (RE=Y3 , La3 and Gd3 ; L=biphenyl 4-carboxylic acid; phen=o-Phenanthroline). The studies of their IR, UV 1H NMR and molar conductivities demonstrate that biphenyl 4-carboylic acid is bounded with RE(Ⅲ) ion. Rare earth ions coordinate with two nitrogen atoms of phen molecules directly in these rare earth complexes. The fluorescence spectra and fluorescence lifetimes of the rare earth complexes show that the fluorescent intensity and lifetime of a series of europium complexes are longer than those of the series of terbium complexes as having the some ligands. There are better fluorescent intensity and lifetime of hetero-nuclear rare earth complexes than homo-nuclear rare earth complexes for europium complexes. The fluorescence emission intensity of Eu3 is raised by inert fluorescent rare earth ions (Y3 , Gd3 and La3 ), but in Tb3 hetero-nuclear rare earth complexes the intensity of Tb3 ions are quenched by the inert fluorescent rare earth ions.