Eu~(2+)和Mn~(2+)激活的碱土金属铝酸盐的阴极射线发光

本文研究了不同Eu~(2+)浓度激活的Sr_4Al_(14)O_(25),BaMg_2Al_(16)O_(27)和BaMgAl_(10)O_(17)铝酸盐的阴极射线发光性质,并与其光致发光性质进行比较。BaMg_2Al_(26)O_(27):Eu~(2+)中掺入Mn~(2+)后可得到发射带半宽度只有27nm的绿色荧光粉。     

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。     

Effect of alkaline metal ions on the photoluminescence properties of Eu~(3+)-doped Ca_3Al_2O_6 phosphors

Ca_3–xAl_2O_6:x Eu~(3+)(0.02≤x≤0.10) and Ca_(2.92)Al_2O_6:0.04Eu~(3+),0.04M~+(M~+=Li~+, Na~+, and K~+) phosphors were prepared by sol-gel method and their photoluminescence properties were investigated. The crystal structure of the annealed Ca_3–xAl_2O_6:x Eu~(3+) and Ca_(2.92)Al_2O_6:0.04Eu~(3+),0.04M~+ phosphors was analyzed with X-ray diffraction(XRD). The size and morphological characteristics of the annealed phosphors were investigated with a field emission scanning electron microscope(FE-SEM). The photoluminescence properties were evaluated with a spectrofluorometer. The phosphors were effectively excited by the light of 396 nm and showed intense red emission at 616 nm, which originated from the 5D_0→7F_2 transition of Eu~(3+). Among the prepared phosphors, the Ca_(2.96)Al_2O_6:0.04Eu~(3+) phosphor showed the strongest emission intensity and the highest color purity. The addition of alkaline metal ions(Li~+, Na~+, and K~+) to Ca_(2.96)Al_2O_6:0.04Eu~(3+) phosphor degraded the emission intensity and color purity.     

Yb~(3+)共掺杂Sr_2MgSi_2O_7∶Eu~(2+),Dy~(3+)长余辉发光材料的制备与性能研究

通过高温固相法制备了Sr_2MgSi_2O_7∶Eu~(2+),Dy~(3+),Yb~(3+)长余辉发光材料。采用XRD、SEM、激发光谱、发射光谱和余辉衰减曲线对Sr_2MgSi_2O_7∶Eu~(2+),Dy~(3+),Yb~(3+)长余辉发光材料的微观结构以及光学性能进行了表征,研究结果表明Sr_2MgSi_2O_7∶Eu~(2+),Dy~(3+),Yb~(3+)长余辉发光材料的晶体结构和显微结构均未发生明显变化。Yb~(3+)的引入使得Sr_2MgSi_2O_7∶Eu~(2+),Dy~(3+)显示出更优良的荧光性能和余辉性能,不同Yb~(3+)掺量对长余辉发光材料的陷阱深度和电子传输速率有显著影响。实验表明,当Yb~(3+)掺杂量为0.03时,Sr_2MgSi_2O_7∶Eu~(2+),Dy~(3+),Yb~(3+)的荧光光谱相对强度最强,且表现出最佳的余辉衰减性能。     

Al_2O3添加物对MgO部分稳定ZrO_2性能的影响

本文研究Al_2O_3添加物对MgO部分稳定ZrO_2(Mg-PSZ)性能的影响。采用ZrO_2,Mg(OH)_2·4MgCO_3·6H_2O和Al_2O_3为原料,配成不同Al_2O-3(0～2％)含量的五种试样,经热塑法成型,>1750℃烧成。试验结果表明:(1)Mg-PSZ中加人Al_2O_3(1～1.5％)能促进烧结、提高其致密度、抗蚀性及抗热震性,但对其电子电导特征氧分压影响不大。(2)添加Al_2O_3的Mg-PSZ的相变温度比ZrO_2原料的相变温度约低100～200℃。(3)添加的Al_2O_3与从c-ZrO_2(ss)脱溶出来的MgO生成镁钼尖晶石,分布于ZrO_2晶界处。     

掺Ce~(3+)、Tb~(3+)的稀土硼酸盐磷光体的合成和发光特性

一、引言硼酸盐体系发光材料的主要特点是灼烧温度低,合成简便、并易于获得高亮度的磷光体。Ce~(3+)激活的稀土硼酸盐的发光,Ce~(3+)—Eu~(2+)激活的卤硼酸盐磷光体以及     

微波辐射法合成Gd_2O_2SO_4∶Eu~(3+)发光材料及性能研究

以Gd_2O_3、Eu_2O_3和NH_4HSO_4为原料,采用微波辐射法合成了Gd_2O_2SO_4∶Eu~(3+)发光材料。并用X射线衍射仪、扫描电镜、荧光光谱仪对所得发光材料的物相、形貌和发光性能进行了表征。结果表明,微波辐射30 min可以合成纯相Gd_2O_2SO_4∶Eu~(3+)发光材料,晶体结构为正交晶系,与Gd_2O_2SO_4结构相同;其形貌不规则,存在团聚现象;Gd_2O_2SO_4∶Eu~(3+)发光材料呈红光发射,发射光谱由一系列铕离子的~5D_0→~7F_j(j=0,1,2,3,4)能级跃迁的尖峰组成,激发光谱主要由处于200 nm～350 nm的宽激发带和位于397 nm和466 nm的窄激发带组成。     

绿松石中亚铁和高铁的测定

绿松石[1]为含铜、铝的磷酸盐矿物。化学式为CuAl_3[PO_4](OH)_8·4H_2O或CuO·3Al_2O_3·2P_2O_5·8H_2O。主要元素含量:CuO=9.78％、Al_2O_3=37.60％、P_2O_5=34.90％、H_2O~+=17.72％。Fe_2O_3最高可达20～21％,但一般不高。由于绿松石中少量铜能被FC~(2+)、Ca~(2+)、     

外场辅助液相法制备红色球形Y_2O_3:Eu~(3+)荧光粉

研究了以尿素为沉淀剂,通过改变加热方式、溶液pH、Eu~(3+)掺杂量及煅烧温度等条件,采用微波辅助液相法制备Y_2O_3:Eu~(3+)红色荧光粉,并对所得荧光粉进行检测分析。结果表明:试验所制备的荧光粉为规整的球形,涂敷性好,可以被近紫外激发光有效激发,发射主峰位于614nm处,归属于Eu~(3+)的~5 D_0→~7 F_2跃迁;该红色荧光粉可应用在白光LED。     

Preparation,structure, luminescence properties of europium doped zinc spinel structure green-emitting phosphor ZnAl2O4:Eu2+

The Zn_(1-x)Al_2 O_4:xEu~(2+) phosphor powders were synthesized by the solid-state reaction method.The synthesis temperature for ZnAl_2 O_4 was optimized,whereas the phase structure,TEM images,photoluminescence(PL) properties,the concentration quenching mechanism,the fluorescence decay curves,as well as the CIE chromaticity coordinates of the samples were investigated in details.Under the excitation at 379 nm,the phosphor exhibits an asymmetric broad-band green emission with a peak at 532 nm,which is ascribed to the 5 d-4 f transition of Eu2+.When the doping concentration of Eu2+ ions is 0.01,the luminescence intensity of the sample reaches the maximum value.It is further proved that the exchange interaction results in the concentration quenching of Eu2+ in the Zn_(1-x)Al_2 O_4:xEu~(2+) phosphor powders.The thermal quenching property of ZnAl_2 O_4:Eu~(2+)phosphor was investigated and the quantum efficiency(QE) values of the selected Zn_(0.99)Al_2 O_4:0.01 Eu~(2+) phosphor was measured and determined as 54.85%.The lifetime of the optimized sample Zn_(0.99)Al_2 O_4:0.01 Eu~(2+) is 3.0852 μs and the CIE coordinate of the sample was calculated as(0.3323,0.5538) with high-color-purity green emission.All properties indicate that the green-emitting ZnAl_2 O_4:Eu~(2+) phosphor powder has potential application in white LEDs.     

红色荧光粉BaAl_2Si_2O_8:Eu~(3+),Li~+的制备和发光性能研究

通过高温固相法合成了红色荧光粉系列Ba_(1-x)Al_2Si_2O_8:Eu_x~(3+),Li_(0.03)~+,并系统地研究了该系列荧光粉的晶体结构和发光性质的变化。合成的试样均为BaAl_2Si_2O_8晶体,均单斜晶系,空间群为C2/m(12)。Eu~(3+)取代Ba~(2+)格位进入基质BaAl_2Si_2O_8晶体,造成了基质晶胞参数a,b,c和晶胞体积V相应地减小,只引起了基质晶体结构轻微的畸变。试样的激发光谱位于220 nm~550 nm,由一个宽带激发谱和一组锐线峰带构成,激发光谱中的最强峰为393 nm(~7F_0→~5L_6)。通过393 nm波段对系列试样进行有效激发,收集到发射光谱均位于550 nm~750 nm,且由发射光谱中出现多条锐线峰,在614 nm(~5D_0→~7F_2)处发射峰最强,Eu~(3+)的595 nm(~5D_0→~7F_1)发射峰劈裂产生了590 nm、595 nm和599 nm处的三个分裂峰,而614 nm(~5D_0→~7F_2)发射峰劈裂为614 nm、617 nm、619 nm、622 nm和627 nm处的五个分裂峰,Eu~(3+)取代Ba~(2+)进入基质晶格BaAl_2Si_2O_8中,与其临近的氧配体形成了C2的点群对称性和Eu~(3+)主要占据非反演对称中心格位。系统研究了该系列荧光粉发光性能与掺杂离子Eu~(3+)浓度的关联。研究结果显示,当掺杂离子Eu~(3+)浓度x≤0.03时,荧光粉的发光强度随着掺杂离子Eu~(3+)浓度x的增加而增加,当x0.03时,随x的增加而减小。试样的色坐标不随掺杂离子Eu~(3+)浓度改变而改变;该系列荧光粉浓度淬灭机理为电偶极–电偶极相互作用。     

Sr_2Al_2SiO_7∶Eu~(2+)发光材料制备及性能研究

采用溶胶凝胶-燃烧还原法在1100℃,p H 3~4的条件下制取了Eu~(2+)掺杂铝硅酸锶发光材料,通过TG-DTA、XRD和荧光光谱分析等方法,研究了材料的结构和发光性能,并对Eu~(2+)不同掺杂浓度下的发光性能进行了对比研究。结果表明,样品干凝胶的分解可以分为熔化、有机物的分解及Sr_2Al_2SiO_7∶Eu~(2+)晶相的生成三个阶段,1100℃所有反应完全;Sr_2Al_2SiO_7∶Eu~(2+)发光材料属于正方晶系晶体结构,其激发光谱是位于峰值344 nm~350nm的宽带谱,发射光谱峰值位于455 nm,最大发射光谱强度为7500 mcd;Eu2+掺杂浓度对其发光性能影响较大,在实验条件下掺杂摩尔浓度为0.04时激发光谱和发射光谱强度均达到最大。     

Sr_(2-x-y)Ca_xMg_yAl_2SiO_7∶Eu~(2+)发光材料的制备及性能研究

采用溶胶凝胶-燃烧法合成Sr_(2-x-y)Ca_xMg_yAl_2SiO_7∶Eu~(2+)稀土长余辉发光材料,通过TG-DTA、XRD、SEM和荧光光谱分析等方法,研究了材料的结构、颗粒形貌和发光性能,并对Ca~(2+)、Mg~(2+)、Eu~(2+)不同掺杂浓度下的发光性能进行了对比研究。结果表明,适量掺杂Ca~(2+)、Mg~(2+)、Eu~(2+)后,基质的晶格结构并未发生变化,为Sr_2Al_2SiO_7晶粒,粒径在1 um~4 um,其激发光谱是位于峰值340 nm~360 nm的宽带谱,发射光谱峰值位于460 nm~480 nm。掺杂Ca~(2+)、Mg~(2+)后发光强度得到提高,镁元素的掺杂可引起发射波长向长波方向移动,而钙元素掺杂可引起发光强度的增大。影响材料发光性能的主要因素是钙,其次是铕,在实验条件下当Ca~(2+)的掺杂量为0.2,Mg~(2+)的掺杂量为0.1,Eu~(2+)的掺杂量为0.04时发光强度为最大,其发射光谱峰值位于469 nm处,最大发射光谱强度达到了8500。     

硼磷酸锶:铕(Ⅱ)荧光粉的合成和应用

前言硼磷酸锶:铕(Ⅱ)是最近新开发的光致发光材料,其化学式可表示为2(Sr_1—xEu_x)·O·mP_2O_5·nB_2O_3,由Eu~(2+)的4f~65d→4f~7跃迁产生宽谱带辐射,发射主峰在480nm。它不仅能为253.7nm汞蒸气的短波紫外光激发,而且还具有吸收405nm、436nm汞     

Eu~(3+)/Sm~(3+)共掺K_2Gd(WO_4)(PO_4)荧光粉的发光性能及热稳定性研究

采用高温固相法制备了K_2Gd_(1-x-y)(PO_4)(WO_4):x Sm~(3+),y Eu~(3+)新型红色荧光材料,通过利用X射线衍射谱(XRD)、荧光光谱对其结构及发光性能进行了研究。结果表明,稀土离子S~(3+)的掺入没有改变荧光粉的晶相;样品的激发光谱在394 nm有很强的激发峰,与近紫外LED芯片匹配,且Eu~(3+)的~5D_0→~7F_2电偶极跃迁表现出616 nm有较好的红光发射,Eu~(3+)的最佳掺杂量(摩尔分数)为y=0.3;Sm~(3+)进入晶格后,激发峰明显增强和变宽,表明Sm~(3+)对Eu~(3+)的发光起到敏化作用;K_2Gd_(0.68)(PO_4)(WO_4)∶0.3Eu~(3+),0.02Sm~(3+)样品在150℃时发光强度仍为初始温度的78%,具有良好的热稳定性且色纯度高,是一种潜在的白光LED用荧光粉。     

Enhanced afterglow performance of CaAl_2O_4:Eu~(2+),Nd~(3+) phosphors by co-doping Gd~(3+)

In order to effectively improve the afterglow properties of CaAl_2 O_4:Eu~(2+),Nd~(3+) phosphors,a series of Ca_(0.982-x)Al_2 O_4:0.012 Eu~(2+),0.006 Nd~(3+),xGd~(3+)(x=0,0.012,0.024,0.036,0.048,0.060 mol) phosphors were prepared by a high-temperature solid-phase approach.Crystalline composition and microstructure were characterized by XRD,TEM,HRTEM,and XPS,luminescence properties were systematically analyzed by fluorescence spectra,afterglow decay curves and TL glow curve.Results show that all of Ca_(0.982-x)Al_2 O_4:0.012 Eu~(2+),0.006 Nd~(3+),xGd~(3+)phosphors belong to monoclinic CaAl_2 O_4,without other cystalline phase.The blue emission at 442 nm is observed,which is assigned to the 4 f~65 d→4 f~7 transition of Eu~(2+) ions.Doping with appropriate amount of Gd~(3+) ions(x=0.036 mol) significantly improves the afterglow properties of phosphors,but the excessive doping of Gd~(3+) induces the fluorescent quenching.The doping of moderate Gd3+changes the traps states,the trap depth varies from 0.598 to 0.644 eV and the trap concentration is also greatly improved,thus significantly improving afterglow performance.     

不同反应条件对焦磷酸锶:铕(Ⅱ)磷光体发光性能的影响及其机制

焦磷酸锶:铕(Ⅱ)由于具有与重氮感光体光敏区相匹配的发射光谱,近二十年来被广泛用作重氮复印灯用荧光粉。Wanmakev et al和Logas对它的发光性质作了初步的研究,Gremer等确定了Sr_2P_2O_7的结构。焦磷酸锶:铕(Ⅱ)通常是以SrHPO_4、(NH_4)_2HPO4、Eu_2O_3为原料,干法混合后,经高温灼烧制成。文献报导了将H_3PO_4加入含Eu_2O_3的SrCO_3,经复分解反应得含Eu~(3+)的SrHPO_4,再经还原性气氛高温灼烧成Sr_(2-x)P_2O_7∶XEu(Ⅱ)的合成方法。     

氧离子浓度对CaAlSiN_3:Eu~(2+)荧光材料温度特性的影响

采用高温固相法合成了氮化物荧光材料CaAlSiN_3:Eu~(2+),研究了不同氧含量时CaAlSiN_3:Eu~(2+)发光性能的变化。当氧含量为2.5%时,得到了最高的发光强度和最佳的温度猝灭性能。从CaAlSiN_3:Eu~(2+)结晶性能以及CaAlSiN_3基质能带结构的变化等方面分析了氧离子浓度变化引起CaAlSiN_3:Eu~(2+)发光性能改变的原因。     

配位体修饰下Eu~(3+)掺杂CaF_2和LaF_3荧光粉发光性能的研究

采用微波法成功合成了具有特殊荧光性质的Eu~(3+)掺杂LaF_3和CaF_2荧光粉。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、光致发光光谱(PL)等分析手段对样品的结构、形貌以及发光性能进行了表征。深入探讨了酒石酸钠、Eu~(3+)掺杂量对合成荧光粉发光性能的影响。实验结果表明,酒石酸钠添加量和Eu~(3+)的掺杂量对其荧光性能具有较大影响;摩尔比的变化使Eu~(3+)从磁偶极跃迁占主导转化为电偶极跃迁占主导,进而使主峰位置从之前的588 nm处变成613 nm处。但没有引起其他峰位置的变化,说明Eu~(3+)进入了LaF_3和CaF_2的晶格之中,而没有其他的变化。     

Green and red phosphor for LED backlight in wide color gamut LCD

Wide color gamut(WCG) backlight for liquid crystal display(LCD) utilizing white light-emitting diodes(LED) has attracted considerable attention for their high efficiency and color reduction.In this review,recent developments in crystal structure,luminescence and applications of phosphors for wide color gamut LED backlight are introduced.As novel red phosphors,Mn~(4+)activate fluoride and aluminate phosphors are advanced in quantum efficiency,thermal quenching and color saturation for their characteristic spectrum with broad excitation band and linear emission.The crystal structure and fluorescence properties of Mn~(4+)doped fluosilicate,fluorogermanate,fluotitanate,as well as Sr_4 Al_(14)O_(25),CaAl_(12)O_(19) and BaMgAl_(10)O_(17) phosphors are discussed in detail.A serial of narrow-band red-emitting Eu~(2+),Eu~(3+)and Pr~(3+)-doped nitride silicates and molybdate phosphors are also introduced.Rare-earth-doped oxynitride and silicate green-emitting phosphors have attracted more and more attention because of the wide excitation,narrow emission,high quenching temperature,high quantum efficiency,such as β-sialon:Eu~(2+),Ba_3Si_6O_(12)N_2:Eu~(2+),MSi_2O_2N_2:Eu~(2+)(M=Ca,Sr,Ba),y-AlON:Mn~(2+)and Ca_3Sc_2Si_3O_(12):Ce~(3+).All above phosphors demonstrate their adaptability in wide color gamut LCD display.Especially for Mn~(4+)doped fluosilicate red phosphor and β-sialon:Eu~(2+)green phosphor.To achieve an ultra-high color gamut in white LED backlight and against the OLED,innovative narrow-band-emission red and green phosphor materials with independent intellectual property rights are continuously pursed.