ChemInform Abstract: Host‐Sensitized Photoluminescence and Coordination Environment Evolution in Ba₆ (Bi_1‐xTb_x)₉B₇₉O₁₃₈ (0 ≤ x ≤ 1).

Abstract

6(Bi1-xTbx)9B79O138 (0  x  1). -The title compounds are prepared by solid state reaction of H 3BO3 (10% excess), Bi2O3, BaCO3, and Tb4O7 (staged heating, 700-850 C, 15 h). Host-sensitized photoluminescence (PL) is confirmed as a result of the efficient Bi 3+ -to-Tb 3+ energy transfer. Furthermore, a structural change in the coordination environments of the Bi 3+ /Tb 3+ sites is observed with increasing x. This evolution, the lowering of the symmetry of the crystal field around Tb 3+ , correlates with variations of the PL spectra. In particular, the value of the ratio of cyan/green (defined as I( 5 D4 7 F6)/I( 5 D4  7 F5) of Tb 3+ ) is  0.28 for x < 0.4, increases to 0.71 at x = 0.9, and then remains almost constant. Ba 6(Ln0.3-yBiyTb0.7)9B79O138 (Ln: La, Y; 0  y  0.3) are also prepared with Ba 6(Ln0.1Bi0.2Tb0.7)9B79O138 showing the strongest emission in both series. -(LI, Q.; CONG*, R.; GAO, W.; YANG, T.; Eur. J. Inorg. Chem. 2015, 30, 5045-5052, http://dx.doi.org/10.1002/ejic.201500622 ; Coll. Chem. Chem. Eng., Chongqing Univ., Chongqing, Sichuan 400044, Peop. Rep. China; Eng.) -J. Schramke 01-006