利用高温固相反应法合成了Ca2-xEuxSnO4发光粉末样, 采用X射线衍射技术和荧光光谱等测试手段对样品的固相反应形成机理及光谱特性进行了研究. 对于CaCO3和SnO2(2:1)混合粉料, 在1250℃进行固相反应时将优先反应生成不稳定的中间相CaSnO3, 该相再与CaO继续反应生成最后稳定的目标相Ca2SnO4. Ca2-xEuxSnO 4样品在240～360nm范围内存在着Eu3+-O2-电荷迁移吸收带, 随着Eu3+掺杂浓度(x=0.01～0.15)的增加, 吸收带峰位从274nm红移至292nm附近. Ca2SnO4:Eu3+发光体的发射以电偶极跃迁2D0-7F2为主导地位, 在紫外光激发下产生强的红光发射. 在Ca2SnO4基质中, Eu3+离子的多声子弛豫过程几率小, 当Eu3+掺杂浓度较低时, 可以观察到来自于Eu3+较高激发态能级5D2和5D1上的辐射跃迁. Eu3+离子在同构的Ca2SnO4和Sr2 eO4基质中的发射光谱形状类似, 但Ca2SnO4:Eu3+的红光发射强度远大于Sr2CeO4:Eu3+.
Eu3+ doped Ca2SnO4 powder samples were prepared by a solid-state method and their formation mechanism and luminescent properties were investigated. When the starting powder mixture of CaCO3 and SnO2 (2:1) is calcined at 1250℃, the unstable intermediate phase CaSnO3 is developed, which then reacts with CaO to form the final product Ca2SnO4. The excitation spectra of Ca 2-xEuxSnO4 show broad Eu 3+-O2- charge-transfer bands with the peak locations changing from 274nm to 292nm by increasing Eu3+ concentrations (x=0.01--0.15). Under UV excitation, the Ca2SnO4:Eu3+ phosphor exhibits novel red emission at about 618nm which is assigned to the 2D-7F2 electric-dipole transition. In addition, the weak emission transitions from the higher 5D2 and 5D1 excited states can be observed at low Eu3+ concentrations because of the low multiphonon relaxation probability. The spectral shape of the Eu3+ emission of Ca2SnO4:Eu3+ is similar to that of its isostructural compound Sr2CeO4 :Eu3+ , however, the red emission from the former is much stronger than that from the latter.
参考文献
| [1] | Dirksen G J, Blasse G. J. Alloys. Comp., 1993, 191: 121--125. [2] Schaik W V, Blasse G. J. Lumin., 1994, 62: 2032--2036. [3] Danielson E, Devenney M, Giaquinta D M, et al. Science, 1998, 279 (6): 837--839. [4] Danielson E, Devenney M, Giaquinta D M, et al. J. Mol. Struct., 1998, 470: 229--235. [5] Sankar R, Subba Rao G V. J. Electrochem. Soc., 2000, 147: 2773--2777. [6] 揣晓红, 张洪杰, 李福#[10], 等. 无机化学学报, 2003, 19 (5): 462--466. [7] Nag A, Narayanan Kutty T R. J. Mater. Chem., 2003, 13: 370--376. [8] 符史流, 尹涛, 丁球科, 等. 物理学报, 2006, 55 (9): 4940--4945. [9] 李沅英, 陈火阳, 扬燕生. 高等学校 化学学报, 1993, 14 (6): 760--763. [10] Yang H M, Shi J X, Gong M L. J. Solid State Chem., 2005, 178: 917--920. [11] Pfaff G. Mater. Sci. Eng. B, 1995, 33: 156--161. [12] Blasse G. J. Solid State Chem., 1972, 4: 52--56. [13] 符史流, 戴军, 丁球科(FU Shi-Liu, et al). 无机材料学报(Journal of Inorganic Materials), 2006, 21 (2): 357--362. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%