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1.
利用高温固相反应法合成了Eu3 掺杂的MCeO3(M=Sr,Ba)发光粉末样品,采用X射线衍射技术和荧光光谱等测试手段分别对其物相组成和发光性质进行了研究。X射线衍射结果显示,Eu3 离子容易替代MCeO3晶格中M2 离子的位置。荧光光谱测试结果表明,Eu3 掺杂的SrCeO3和BaCeO3样品在紫外波段存在着非常宽的吸收带,峰值分别位于311和320nm左右,它们属于Ce4 -O2-的电荷迁移带,SrCeO3和BaCeO3基质与Eu3 离子之间存在着能量转移。在MCeO3∶Eu3 样品中,Eu3 的发射主要来自于5D0激发态能级,其中以磁偶极跃迁5D0—7F1发射强度为最大;此外样品中还存在着较高的5D1激发态能级的辐射跃迁。SrCeO3∶Eu3 样品的发射强度远大于BaCeO3∶Eu3 样品。 相似文献
2.
利用高温固相反应法合成了Eu^3+掺杂的MCeO3(M=Sr,Ba)发光粉末样品,采用X射线衍射技术和荧光光谱等测试手段分别对其物相组成和发光性质进行了研究。X射线衍射结果显示,Eu^3+离子容易替代MCeO3晶格中M^2+离子的位置。荧光光谱测试结果表明,Eu^3+掺杂的SrCeO3和BaCeO3样品在紫外波段存在着非常宽的吸收带,峰值分别位于311和320nm左右,它们属于Ce^4+-O^2-的电荷迁移带,SrCeO3和BaCeO3基质与Eu^3+离子之间存在着能量转移。在MCeO3:Eu^3+样品中,Eu^3+的发射主要来自于^5D0激发态能级,其中以磁偶极跃迁^5D0-^7F1发射强度为最大;此外样品中还存在着较高的^5D1激发态能级的辐射跃迁。SrCe03:EU^3+样品的发射强度远大于BaCeO3:EU^3+样品。 相似文献
3.
Upconversion Luminescence of Eu3 + in NaYbF4∶ Tm3 + , Eu3 +Nanocrystals Induced by 980 nm Excitation
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利用水热法制备得到NaYbF4∶0.01%Tm3+,20% Eu3+上转换材料,利用X射线衍射分析、扫描电子显微镜及光谱测试技术分别对其进行了结构、形貌以及光谱性质的表征.在980 nm近红外激光激发下,得到了Eu3+的可见到紫外范围的上转换荧光发射.分析表明:共掺杂NaYbF4纳米材料中Tm3+到Eu3+离子的能量传递对布居Eu3+离子的激发态能级,获得Eu3+的上转换发光起着至关重要的作用.另外,在实验中首次获得了Eu3+对应于3P0→7Fj(j=0,1,2)能级跃迁的上转换光发射. 相似文献
4.
ZnO:Eu3+纳米晶的制备及发光性质研究 总被引:4,自引:0,他引:4
为了探讨稀土Eu3 与纳米ZnO基质之间的能量传递,利用溶胶-凝胶法(Sol-Cel)制备了ZnO:Eu3 纳米晶,测量了样品的X射线衍射谱(XRD)、光致发光谱(PL)和激发谱(PLE).X射线衍射结果表明,ZnO:Eu3 具有六角纤锌矿晶体结构.观察到稀土Eu3 强而窄的特征发射和ZnO基质弱而宽的可见发射.分析了稀土Eu3 激发态5D0→7F1,5D0→7F3和5D0→7F2特征发射机制.给出了Eu3 离子特征发射的峰值强度随掺Eu3 浓度增加而增强的变化关系,证实了纳米ZnO基质与稀土Eu3 离子之间存在能量传递.比较了Eu3 离子5D0→7Fl磁偶极跃迁(MD)与5D0→7F2电偶极跃迁(ED)的相对强度,证实了在ZnO纳米晶基质中大多数Eu3 占据了对称性较低的格位. 相似文献
5.
采用高温固相法制备了KBaPO4:Eu3+红色发光材料,研究了Eu3+掺杂浓度、电荷补偿剂等对材料发光性质的影响,并利用X射线衍射及光谱等技术对材料的性能进行了表征.研究结果显示:在400 nm近紫外光激发下,材料呈多峰发射,分别由Eu3+的5D0→7FJ(J=0,1,2,3,4)能级跃迁产生,主峰位于621 nm|监测621 nm发射峰,所得激发光谱由O2-→Eu3+电荷迁移带(200~350 nm)和f-f高能级跃迁吸收带(350~450 nm)组成,主峰位于400 nm|改变Eu3+掺杂浓度,KBaPO4∶Eu3+材料的发射强度随之改变,Eu3+浓度为5 mol%时,强度最大|依据Dexter理论,得知引起浓度猝灭的原因为电偶极-电偶极相互作用|添加电荷补偿剂,可增强KBaPO4∶Eu3+材料的发射强度,其中以添加Li+,Cl-时,材料发射强度提高最明显. 相似文献
6.
采用共沉淀方法制备了稀土离子Eu3+,Dy3+,Sm3掺杂的Ca(Sr,Ba) WO4发光材料,目的是研究金属阳离子改变对稀土离子发光性质的影响.X射线衍射光谱数据表明,CaWO4、SrWO4、BaWO4都是四方晶系I41/a(88)结构,随着阳离子半径增大,衍射峰向小角移动.不同温度制备的BaWO4样品X射线衍射光谱数据表明,温度较低时制备的晶体样品X射线衍射峰较宽;当制备温度升高后,晶体样品X射线衍射峰宽变窄.样品的SEM照片表明,低温制备的样品晶粒尺寸较小,约为100~300 nm;高温制备样品晶粒尺寸较大,约为2~6 μm.测试了Eu3+,Dy3+,sm3+掺杂的Ca( Sr,Ba) WO4发光材料的激发和发射光谱.计算了Eu3+掺杂的Ca(sr,Ba) WO.的J-O强度参数Ωλ(λ=2,4),Ω2值随着阳离子半径增大迅速减小,经分析它是导致Eu3+掺杂的Ca(Sr,Ba) WO4的发射强度随着阳离子半径增大迅速减弱的原因.然而Sm3+掺杂的SrWO4其他两种晶体相比,其发射强度反而增强.根据激发光谱和文献报道,我们认为可能是由于钨酸根离子与稀土离子的能量传递引起的.从Dy3+,Sm3+掺杂的Ca(Sr,Ba)WO4的发射光谱可以看到,随着阳离子半径增大发射峰蓝移,发射峰的Stark劈裂减弱.我们用位形坐标图解释了这一现象产生的原因. 相似文献
7.
利用共沉淀法制备了纳米晶Gd2O3:Eu3+发光粉体. 在不同掺杂浓度、不同煅烧温度的系列样品中,均观测到Eu3+离子的特征发射.样品的晶相与发射性质的研究表明:所制备的样品经800~1 300 ℃热处理后,晶相为立方相,1 400 ℃时开始向单斜相转变.荧光强度与Eu3+离子掺杂浓度关系研究表明:在不同掺杂浓度中,Eu3+离子浓度为4%时其相对发射强度最强.在三个不同的煅烧温度中,经800 ℃煅烧的样品其发光效果最好.此外还观察到电荷转移激发态以及基质、Gd3+与Eu3+之间的能量传递.激发谱包含三部分,即电荷转移带、Eu3+的4f内壳层电子跃迁和Gd3+的激发谱. 相似文献
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掺杂Eu3+离子LaPO4的合成及其发光特性研究 总被引:8,自引:3,他引:5
采用固相反应法合成了掺杂Eu3+离子的LaPO4,并用X射线粉末衍射对其结构进行了表征.XRD数据经计算机处理表明:LaPO4属单斜晶系,晶胞参数a=6.84A,b=7.08A,c=6.46A,β=103.85°,属P21/n(No.14)空间群.测定了其激发光谱和发射光谱,光谱数据表明:在掺杂Eu3+离子的LaPO4荧光体中,基质LaPO4的电荷迁移激发态的能量能有效地传递到Eu3+离子,说明基质LaPO4本身对发光有贡献.位于592,612 nm附近的2个发射峰均出现劈裂现象,即有2个5D0→7F1(590,594nm)、2个5D0→7F2(610,614nm)发射峰,说明掺杂的Eu3+离子在LaPO4晶体中有着不相同的配位环境,推测Eu3+离子处于D2d或D3对称格位. 相似文献
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11.
Summary We report the measurements of the3
D(3s4d)-3
P(3s3p)3
D(3s5d)-3
P(3s3p), and3
P(3p
2)-3
P(3s3p) transition frequency of MgI, the fine-structure separation and isotope shift between24Mg and26Mg. The measurements have been performed in a metastable atomic beam; a good agreement is found for data already existing
in the literature. The accuracy of the measurements reported in this paper is mainly limited by the Doppler broadening of
theI
2 transitions used as a reference and by the precision in the knowledge of the related wavelengths. 相似文献
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The systematic application of band contour techniques to account for most of the observed features of the ir spectra of s-triazine and s-triazine-d3 have been made as well as a critique as to the limitations of such methods. The experimental and computer methods used to study the gas phase infrared band contours of s-triazine and s-triazine-d3 are out-lined. Contours of the five E′ fundamentals of s-triazine have been recorded under moderate resolution and analyzed to give the Coriolis constants , i = 6–10. The effects of l-resonance are very apparent for ν8 and ν9, in the form of holes in the Q branches of these bands. Under the highest resolution available, ν6 and ν10 also show l-resonance effects. Values of the l-doubling constants were obtained for these four fundamentals. One of the parallel A2″ fundamentals of C3H3N3 (ν12) has also been studied. It lies close to ν10(E′) and an A × E type of second-order Coriolis resonance may be the cause of the intensity enhancement observed in the inner wings of the ν12 and ν10 bands. Hot bands of the type (νi + nν14 ? nν14) have been observed in the contours of ν8, ν10, and ν12. This is felt to be responsible for the large difference between our observed zeta sum (?1.30) and the theoretical sum (?1.00).The gas phase infrared band contours of the five E′ and 2A2″ fundamentals of C3N3D3 have also been recorded under moderate resolution. From P-R separations and by computer simulation of the contours, values of the Coriolis constants have been obtained for the E′ modes. The effects of l-resonance have been observed for ν8(E′) and ν10(E′) and values of the l-doubling constants have been estimated. An extensive series of hot bands of the type (ν12 + nν14 ? nν14) has been observed in the contour of the ν12 (A2″) fundamental. The mass effect on the Coriolis constants has been discussed.Infrared band contours of the overtone 2ν7 and seven degenerate E′ combination bands of C3N3H3 have been recorded under moderate resolution. Analysis of these contours using the P-R separation method and computer simulation of the contours has given values of for these bands. Fermi resonance between 2ν7 and ν6 has been analyzed. The importance of considering both the observed contour as well as the observed frequency when assigning higher tone bands is illustrated. 相似文献
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P. A. Markovin V. V. Lemanov M. E. Guzhva P. P. Syrnikov T. A. Shaplygina 《Physics of the Solid State》2014,56(5):989-995
The temperature dependences of the dielectric constant and dielectric hysteresis loops in ceramic samples of (1 ? x)SrTiO3?x KNbO3 and (1 ? x)SrTiO3?x KTaO3 (0 ≤ x ≤ 0.3) solid solutions prepared using different heat treatments have been investigated. Phase diagrams of the studied solid solutions have been constructed in the T-x coordinates. It has been shown that, after quenching of samples (spontaneous cooling at room temperature after long-term heating at the sintering temperature of the ceramic samples), the temperature of the induced phase transition increases because of the weakening of random electric fields associated with nonisovalent impurities due to their “frozen” nonequilibrium redistribution. For small concentrations x, strong dielectric relaxation is observed in the temperature range of 150–250 K. A model of relaxing centers, which is based on the local charge compensation of heterovalent impurities, has been proposed. 相似文献
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The infrared spectra of ammonia-borane, BH3NH3, and two of its deuterated isotropic species, BD3ND3 and BH3ND3, isolated in argon matrix at liquid hydrogen temperature have been measured. Well resolved bands for these three isotopic species have been observed for all the fundamentals. A complete frequency assignment based on C3v molecular symmetry has been made. A set of force constants have been calculated from the data for the two isotopes BH3NH3 and BD3ND3 using a valence force field. The agreement between experiment and frequencies calculated from these force constants for the mixed isotopic species, BH3ND3, substantiates the present assignment. 相似文献
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JETP Letters - Films of CH3NH3PbI3 organometallic perovskite, which is currently considered as a promising basic material for new-generation solar cells, as well as films containing CsPbI3... 相似文献
19.
Knorr K. Loidl A. Stühn B. Buevoz J. L. 《Zeitschrift für Physik B Condensed Matter》1981,41(4):315-320
Neutron diffraction experiments have been carried out on the magnetically ordered phases of ErPb3, HoPb3, ErTl3 and HoTl3. The magnetic moments were found to be sinusoidally modulated with a propagation vector of (0, 0.2, 0.5) for the Pb-compounds and (0.38, 0.38, 0.16) for the Tl-compounds.Work supported by the Bundesministerium für Forschung und Technologie 相似文献
20.
(LaO)3BO3中Eu^3+和Sm^3+的光致发光 总被引:4,自引:2,他引:2
研究了紫外光激发下,(LaO)3BO3基质中Eu^3+和Sm^3+的光谱性质,Eu^3+和Sm^3+的电荷迁移激发带及发光强度随组成和结构变化的规律性,并探讨了Eu^3+和Sm^3+自身浓度猝灭的机理。 相似文献