Systematic study of photoluminescence upon band gap excitation in perovskite-type titanates R1/2Na1/2TiO3:Pr (R = La, Gd, Lu, and Y)
Systematic study of photoluminescence upon band gap excitation in perovskite-type titanates R1/2Na1/2TiO3:Pr (R = La, Gd, Lu, and Y)
复制标题
DOI：
10.1016/j.jssc.2007.03.017
复制
发表时间：
2007-05-01
影响因子：
3.3
通讯作者：
Katsumata, Tetsuhiro
中科院分区：
文献类型：
--
作者：
Inaguma, Yoshiyuki;Tsuchiya, Takeshi;Katsumata, Tetsuhiro
合成了Pr~(3+)掺杂的钙钛矿材料R1/2Na1/2TiO_3：Pr(R=La，Gd，Lu，Y)，研究了它们的结构、光吸收和发光性能，讨论了结构与光学性能的关系。R1/2Na1/2TiO3的光学带隙按R=La，Gd，Y和Lu的顺序增加，这主要是由于带宽的减小和Ti-O-Ti键角的减小所致。在带隙光激发下，所有化合物都观察到了Pr3+从激发态D-1(2)到基态H-3(4)的f-f跃迁的强红光发射。发射峰的波长按R=La，Gd，Y，Lu的顺序红移，这源于Pr3+晶场分裂的增加。这归因于Pr0原子间距的减小和(R，Na)-O原子间距的减小，即Pr和O之间共价性的增加。结果表明，Rl/2Na1/2TiO3：Pr的发光性质是由Pr3+的基态和激发态4f(2)之间的相对能级以及导电性和价带决定的，这主要取决于结构，如TiO6八面体的倾斜度、Pr-Ti原子间的距离和Pr离子的位置对称性。(C)2007 Elsevier Inc.保留所有权利。
Pr3+-doped perovskites R1/2Na1/2TiO3:Pr (R = La, Gd, Lu, and Y) were synthesized, and their structures, optical absorption and luminescent properties were investigated, and the relationship between structures and optical properties are discussed. Optical band gap of R1/2Na1/2TiO3 increases in the order R = La, Gd, Y, and Lu, which is primarily due to a decrease in band width accompanied by a decrease in Ti-O-Ti bond angle. Intense red emission assigned to f-f transition of Pr3+ from the excited D-1(2) level to the ground H-3(4) state upon the band gap photo-excitation (UV) was observed for all compounds. The wavelength of emission peaks was red-shifted in the order R = La, Gd, Y, and Lu, which originates from the increase in crystal field splitting of Pr3+. This is attributed to the decrease in inter-atomic distances of Pr 0 together with the inter-atomic distances (R, Na)-O, i.e., increase in covalency between Pr and O. The results indicate that the luminescent properties in R1/2Na1/2TiO3:Pr are governed by the relative energy level between the ground and excited state of 4f(2) for Pr3+, and the conduction and valence band, which is primarily dependent on the structure, e.g., the tilt of TiO6 octahedra and the Pr-Ti inter-atomic distance and the site symmetry of Pr ion. (c) 2007 Elsevier Inc. All rights reserved.