B-site ordered double perovskite LaBa1−xSrxZnSbO6 (0 ≤ x ≤ 1): Sr2+-doping-induced symmetry evolution and structure–luminescence correlations. Issue 9 (2nd February 2016)

• Record Type: Journal Article
• Authors: Jiang, Pengfei; Zhou, Zhengyang; Gao, Wenliang; Cong, Rihong; Yang, Tao
• Is Part Of: Dalton transactions. Volume 45:Issue 9(2016)
• Page Start: 3949
• Page End: 3957
• Publication Date: 2016-02-02
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c5dt04150c
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : With Sr 2+ substitution, the ordered perovskite structure of LaBa1− x Sr x ZnSbO6 evolved from I 2/ m to P 21 / n, together with a change of Eu 3+ luminescence. Abstract : The study of perovskites has been active for a long time. Here, we rationally designed and prepared a double perovskite, LaBaZnSbO6, by selecting Zn 2+ and Sb 5+ with large size and charge differences, and, indeed, complete B-site ordering can be achieved. Careful study using powder X-ray diffraction data pinpointed its space group to be I 2/ m, which has rarely been seen in double perovskites. Thereafter, an interesting observation of Sr 2+ -doping-induced symmetry evolution from I 2/ m to P 21 / n was confirmed in the complete solid solutions LaBa1− x Sr x ZnSbO6, where the tilting system also transferred from a − a − c 0 to a − a − c + . The transition boundary is around x = 0.4. It can also be visualized by the variation of θ (defined as c /[( a + b )/2]), which is associated with the anisotropic shrinkage of the unit cell lattice and indeed shows a minimum at x = 0.4. Such a successive modulation of both the structural symmetry and the average La/Ba/Sr–O bond distances (revealed by Rietveld refinements) motivated us to study the Eu 3+ luminescence in La0.95 Eu0.05 Ba1− x Sr x ZnSbO6 . Interestingly, the maximum of charge transfer absorption of Eu 3+ shows a precise changing tendency with the A–O bond distances along with the Sr 2+ doping, clearly revealing the structure–luminescence correlations.