首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 57 毫秒
1.
Eu3+和Tb3+掺杂的Y2SiO5体系发光特性研究   总被引:10,自引:0,他引:10  
采用溶胶-凝胶法合成了Eu^3 和Tb^3掺杂的Y2SiO5基发光材料,通过测量它们的激发光谱和发射光谱,研究了它们的发光特性,探讨了材料中Tb^3和Eu^3 两种发光中心间的能量关系。结果表明,Eu^3+在其中的特征发射以^5D0→^7F2电偶极跃迁为,Eu^3处于非反演对称中心格位;Tb^3在其中的发射为^5D4→^7FJ(J=4-6)跃迁发射。当Eu^3和Tb^3共存于Y2SiO5基质中时Eu^3的发射增强,Tb^3的发射减弱,存在Tb^3→Eu^3能量传递,Tb^3对Eu^3具有敏化作用。  相似文献   

2.
LaPO4:Ce3+/Tb3+ 纳米线的合成和发光特性   总被引:2,自引:0,他引:2  
通过水热法合成出Ce^3 和Tb^3 共激活的LaPO4纳米线,并同相应的微米棒进行了比较。研究了其荧光光谱和动力学过程。结果表明纳米线和微米棒的晶体结构均为单斜相。在单掺杂Ce^3 和Tb^3 的材料中,微米棒的发光强度与纳米线相比稍有提高,但在共掺杂的纳米线样品中对应Ce^3 的激发,Tb^3 的^5D4→^7F5绿光发射比微米棒提高了3~5倍。通过动力学研究,纳米线中Ce^3 和Tb^3 的电子跃迁速率与微米棒对比没有显著的提高,且Ce^3 →Tb^3 的能量传递速率降低了3倍。Tb^3 的^53能级衰减包括两个过程:快过程和慢过程。纳米线以慢过程为主,而微米棒以快过程为主。我们认为慢过程对应^5D3→^5D4的弛豫,快过程对应^5D3向其他缺陷能级的跃迁。因此共掺杂纳米线中强度的提高被归因于在纳米线中更多的边界阻碍而引起在高于^5D4的激发态能级上损失的能量更少。  相似文献   

3.
研究了Tb^3 和Eu^3 在LnBaB9O16(Ln=La,Gd,Y,Lu)中的紫外和真空紫外光谱性质。X射线粉末衍射数据指标化结果表明,LnBaB9O16(Ln=La,Gd,Y,Lu)系列化合物属于三方晶系.Eu^3 的荧光光谱结果表明,LaBaB9O16和GdBaB9O16中稀土离子占据非中心对称的格位,Eu^3 在其中的特征发射以^5D0→^7F2电偶极跃迁为主;而在YBaB9O16和GdBaB9O16中稀土离子占据中心对铱性的格位,E^3 在其中的特征发射以^5D0→^7F1磁偶极跃迁为主.Tb^3 在LaBaB9O16和GdBaB9O16中的发射为^5D3→^7F0和^5D4→FJ(J=0-6)辐射跃迁,在YBaB9O16和LuBaB9O16中只能观察到^D4→^7FJ(J=3-6)辐射跃迁。与Eu^3 的发光性质相反,Tb^3 占据非中心对称的格位时的发射强度比占据中心对称的格位时要弱得多.Eu^3 和Tb^3 掺杂的样品在真空紫外波段的吸收弱。  相似文献   

4.
We experimentally investigated the VUV excitation luminescence properties of Ca4 GdO(B03)3 :RE (RE=Eu^3 , Tb^3 )Ca4GdO(BO3)3:Eu3 and Ca4GdO(BO3)3:Tb^3 emitted bright red and green colour light, respectively, under 172 nm excitation, resulting from the favorable position of the host absorption band (186 nm) and efficient energy transfer from Gd^3 to activators (e.g. Eu^3 or Tb^3 ) by means of secondary absorption in the Ca4GdO(BO3)3 matrix. The f-d transitions of Eu^3 and Tb^3 in the host lattice are depicted.  相似文献   

5.
在本文中制作了CaAl4O7:Tb^3 ,Ce^3 新荧光材料。烧结温度为1300℃,烧结环境为N2+5%H2还原气。TEM实验结果表明样品的粒度小于1μm。X-射线和HRTEM实验证实,样品的晶格点阵十分规则,而且没有发现掺杂和助溶剂对基质结构的影响,表现出十分好的材料质量。光学实验观测到对应于Tb^3 离子的^5D4到^7FJ(J=6,5,4,3)的跃迁发射峰在485,545,590和630nm。CaAl4O7:Tb^3 ,Ce^3 降低了基质结构的不确定性,同时保持了Tb^3 发光中心的特性。  相似文献   

6.
We investigate the luminescence properties of Bi^3+ and RE^3+ (RE = Tb or Eu) in a Y3Ga5O12 (YGG) host system. The additional doping of Bi^3+ can enhance the luminescence of Th^3+ or Eu^3+ in this host. Energy transfer from Bi^3+ to Tb^3+ and Eu^3+ is observed and the mechanism of energy transfer is investigated. Mechanism of energy transfer can be explained as electric multipole interaction since the Bi^3+ emission band and Tb^3+ or Eu^3+ excitation band overlaps and the Bi^3+ emission intensity decreases while the intensity of Tb^3+ or Eu^3+ increases with the increase of Tb^3+ or Eu^3+ concentration. Therefore, Bi^3+ ion is a kind of efficient sensitizer to the Tb^3+ and Eu^3+ activators in the Y3Ga5O12 host.  相似文献   

7.
Ln(BO3,PO4)[Ln=La,Y]基质中Ce^3+、Tb^3+、Gd^3+的光谱   总被引:3,自引:0,他引:3  
研究了硼磷酸镧和硼磷酸钇基质中Ce^3 、Tb^3 、Gd^3 的发射光谱和激发光谱。结果表明:La(BO3,PO4):Ce,Tb体系中加入钆后,Ce^3 的 发射降低,Tb^3 的发射增强,Y(BO3,PO4):Ce,Tb体系中加入钆后,Ce^3 和Tb^3 的发射均增强,且前者增加的幅度高于后者。因此在La(BO3,PO4):Ce,Tb,Gd体系中Gd^3 离子起着能量传递中间体和敏化剂的作用;在Y(BO3,PO4):Ce,Tb,Gd体系中Gd^3 离子只起敏化剂作用,并且阻碍Ce^3 →Tb^3 的能量传递。与Y(BO3,PO4):Ce,Tb,Gd相比,La(BO3,PO4):Ce,Tb,Gd对紫外吸收强,254nm激发下发出的光绿色纯度,强度大,更适合做荧光灯中的绿粉。  相似文献   

8.
在254nm紫外光(UV)激发下,研究了(LaO)3BO3基质中Tb^3 的激发光谱、发射光谱、发光寿命与Tb^3 浓度的关系,并探讨了Tb^3 的^5D3→^7D3→F4。跃迁发射的自身浓度猝灭机理,在阴极射线(CD)激发下,研究了(LaO)3BO3:Tb^3 的发光强度与Tb^3 浓度、加速电压及电流密度的关系,发现在UV事CR两种激发条件下,试样均能发出明亮的绿色荧光,有望成为一种有发展前途的绿粉。  相似文献   

9.
用高温固相法合成了Sr3B2O6:Tb^3+,Li^+绿色荧光粉,并研究粉体的发光性质。发射光谱由位于黄绿区的4个主要荧光发射峰组成,峰值分别位于495,548,598,625nm,对应了Tb^3+的^5D4→^7F6,^5D4→^7F5,^5D4→^7和^5D4→^7F3特征跃迁发射,548nm的发射最强。激发光谱表现从200—400nm的宽带,可以被近紫外光辐射二极管(near-ultraviolet light-emitting diodes,UVLED)管芯产生的350-410nm辐射有效激发。研究了Tb^3+掺杂和电荷补偿剂对样品发光亮度的影响。Sr3B2O6:Tb^3+,Li^+是一种适用于白光LED的绿色荧光粉。  相似文献   

10.
掺Eu3+硅基材料的发光性质   总被引:9,自引:5,他引:4  
通过溶胶-凝胶技术制备了掺Eu^3 的硅基材料并测试了其三维荧光光谱、激光谱和发射光谱,结果显示,最佳激发波波长为350nm,最强荧光波长为620nm;在350nm光激发下的发射光谱显示Eu^3 的特征发射光谱,产生4条谱带,分别是577nm(^5D0-^7F0),588nm(^5D0-^7F1),596nm(^5D0-^7F1)和610nm(^5D0-^7F2)。  相似文献   

11.
本研究选择三个电子结构类似的稀土倍半氧化物RE2O3(RE=Lu, Y,Sc),建立适当的模型通过第一性原理计算,研究氧空位对体系的电子结构的影响.本研究以密度泛函理论(DFT)为基础,利用PBE泛函加U值修正计算了纯稀土倍半氧化物的能带结构.计算结果表明三种基体材料RE2O3的能带结构相似.在引入氧空位后,其增加的缺陷能级数目不同,依次为:Sc2O32O32O3.  相似文献   

12.
Among amorphous Fe2RE (RE=Er, Ce, Gd, La, Pr, Sm, Dy, Ho) alloys, Fe2Ce exhibits a tendency toward short range order, while the other Fe2RE compounds show clustering. However, we have almost no information about environments around Fe atoms. Using Mössbauer spectroscopy we have determined the quadrupole splitting distributionsP(QS) of two representative amorphous Fe2RE (RE=Ce, Er) alloys, leading to local environments of Fe atoms. The analysis of the mixed magnetic dipole and quadrupole interactions in Fe2Er shows two kinds of electrical field gradients (EFT) with the positive and negative signs in the sample, indicating a random packing of Fe atoms. Furthermore, the analyzed quadrupole splitting distributionP(QS) of Fe2Er also supports random packing in this amorphous alloy. On the other hand, the amorphous Fe2Ce alloy shows two kinds of distributions of quadrupole splitting; the major component indicating random packing and the minor component Ce-rich Ce-Fe clusters.  相似文献   

13.
The thermo-luminescence (TL) of rare earth ions RE3+ (RE=Ln, excluding Pm, Eu and Lu) co-doped phosphors CaGa2S4:Eu2+, RE3+ was studied between room temperature and 300 °C, and 3D thermo-luminescence of the phosphors were measured from room temperature to 400 °C. The basic material CaGa2S4:Eu2+, showed at least two bands in the TL glow curve. Changing the auxiliary activator RE3+ (rare earth ion), intensities and the positions of the TL glow curve peaks were affected significantly. For the phosphors with long afterglow, auxiliary activator such as Ce3+, Pr3+, Gd3+, Tb3+, Ho3+, or Y3+ created some new defects in these compounds at lower trap levels and enhanced their TL intensities. The Nd3+ or Er3+ auxiliary activator only enhanced TL intensities to a low extent, so these two phosphors have short persistent luminescence at room temperature. TL intensities of La3+, Sm3+, Tm3+ or Yb3+ co-doped phosphors were suppressed greatly and no afterglow was shown. The relationship between auxiliary activators and corresponding thermo-luminescence curves of phosphors CaGa2S4:Eu2+, RE3+ are discussed in detail. According to our results, suitable activation energy and enough high corresponding trap density are necessary for the phosphor with long afterglow.  相似文献   

14.
CaAl3BO7:RE(RE=Ce,Gd,Tb)中稀土离子的光谱特性   总被引:2,自引:0,他引:2       下载免费PDF全文
尤洪鹏  洪广言 《发光学报》1997,18(3):191-194
采用固相反应法合成了CaAl3BO7RE(RE=Ce,Gd,Tb),研究了Ce3+,Gd3+和Tb3+的光谱特性。发现铈离子周围存在较强的晶场,使基态的4f能级劈裂较大,从而导致铈离子的特征发射峰重叠较大;Ce3+的5d能级明显低于Gd3+6I、6P能级;Ce3+和Tb3+之间存在有效的能量传递。  相似文献   

15.
RE, Mn:YAP (RE=Yb and Ce) crystals with dimension of Φ 25×60 mm were successfully grown by the Czochralski method. The spectroscopic properties of RE, Mn:YAP (RE=Yb and Ce) crystals before and after γ-irradiation were investigated at room temperature. The results show that the content of Mn4+ ions was increased with the Yb3+ ions co-doping, but decreased by Ce3+ ions co-doping. Thermoluminescence (TL) spectra of the crystals indicate three steps of recombination, and the probable recombination processes were discussed.  相似文献   

16.
The purpose of the present study is to develop an understanding of photoluminescence properties of Dy3+, Mn2+ or Gd3+doped NaCaPO4 phosphors, which have served as efficient phosphors in many industrial applications. The phase formation was confirmed by the X-ray powder diffraction (XRD) measurement. Photoluminescence (PL) excitation spectrum measurement of NaCaPO4:Dy3+ shows this phosphor can be efficiently excited by near-ultraviolet (UV) light from 300 to 400 nm and presents dominant luminescence band centered at 480 nm (blue) and 573 nm (yellow). The PL excitation of NaCaPO4:Mn2+ and Gd3+ under UV wavelength shows the emissions at 520 and 313 nm, respectively. A scanning electron microscope (SEM) shows an average crystallite size in sub-micrometer range. The obtained results show that the phosphors have the potential for application in the lamp industry and medical applications.  相似文献   

17.
The ternary rare-earth metal boride carbides RE5B4C5 (RE=Ce, Pr, Nd) were prepared by arc melting the mixtures of the pure elements and subsequent annealing at 1270 K. Their crystal structures were determined from single crystal X-ray diffraction data. They crystallize in the Ce5B4C5 type of structure (space group Pna21, Z=8). Two new compounds were found, Pr5B4C5: a=24.592(2) Å, b=8.4563(5) Å, c=8.4918(5) Å, R1=0.043 (wR2=0.076) for 2871 reflections with Io?2σ(Io)); for Nd5B4C5: a=24.301(1) Å, b=8.3126(5) Å, c=8.3545(4) Å, R1=0.035 (wR2=0.069) for 3707 reflections with Io?2σ(Io)). Its structural arrangement consists of a three-dimensional framework of rare-earth atoms resulting from the stacking of slightly corrugated two-dimensional square nets, leading to voids filled with B4C4, B3C3, BC2 finite chains and isolated carbon atoms. Ce5B4C5 is an antiferromagnet at 5 K followed by a metamagnetic transition in elevated external fields. Pr5B4C5 and Nd5B4C5 are ferromagnets below TC=12 and 15 K, respectively.  相似文献   

18.
H. Yang 《哲学杂志》2013,93(27):4211-4228
Glass formation has been systematically studied in melt-spun Al-rich Al–Ni–RE (RE?=?La, Ce, Pr, Nd and Mm; Mm?=?misch metal) alloys by navigating the compositions following the observation of microstructure evolution in the resulting ribbons. The optimum glass-forming regions are similarly located around Al85Ni10RE5 and found in the centre of the composites with primary phase α-Al, Al11RE3 and Al3Ni. The similarities in the critical cross-section below which a component is fully amorphous and the optimum compositions in these Al–Ni–RE systems are interpreted in terms of their competing crystalline phases and thermodynamic properties. Interestingly, it is indicated that Ni content is markedly higher than RE content in the best glass-forming alloys, which may be associated with strong interaction between Ni–Al atom pairs and the dense packing due to Ni-centred clusters.  相似文献   

19.
Effect of RE3+ as a co-dopant in long-lasting phosphorescence CdSiO3:Mn2+ (RE=Y, La, Gd, Lu) has been investigated. A longer orange emitting phosphorescence phenomenon was observed in the co-doped CdSiO3:Mn2+,RE3+ phosphors after exciting with ultraviolet (UV) light. The luminescence properties, including photoluminescence (PL) spectra and thermoluminescence (TL) spectra, as well as the afterglow decay curves, were studied. The results revealed that one of the origins of the improvement is due to nonequivalent substitution to produce more e-traps, and energy transfer from Gd3+ to Mn2+ to boost the performance of CdSiO3:Mn2+,Gd3+. Role of RE3+ co-doped into CdSiO3:Mn2+ matrix and the possible long-lasting phosphorescence process are discussed in this paper.  相似文献   

20.
Through altering the solvents, we have obtained the Eu3+/Tb3+ ions-doped LnPO4 (Ln = La, Gd) phosphors with different particle sizes, microstructures and morphologies via a facile solvo-thermal technology. X-ray powder diffraction (XRD), transmission electron microscope (TEM), and scanning electron microscope (SEM) have shown that the products using different solvents have various structures and morphologies. With the increase of DMA/water volume ratio, the microstructure has changed from hexagonal phase to monoclinic one, and the morphology from nanorod to nanoparticle, revealing the decreased oriented growth. The presence of DMA is an important factor in guiding the anisotropic growth of hexagonal lanthanide phosphates. Besides, N-methyl-2-pyrrolidone has been used as solvent to induce the Eu3+/Tb3+ ions-doped LnPO4 (Ln = La, Gd) phosphors with different morphologies and structures. Finally, the photoluminescence behaviors of these nanocrystals have been investigated, which are dependent on their microstructures and morphologies.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号