Approaching the structure of REBaB₉O₁₆ (RE = rare earth) by characterization of a new analogue Ba₆Bi₉B₇₉O₁₃₈

Abstract

Understanding structure-property relationship is the key to rationally design superior materials. REBaB9O16 (RE = La-Lu, Y) is a series of well-known photoluminescent hosts, which has been extensively studied but without any structure details reported. We prepared its new analogue Ba6Bi9B79O138 (BBBO) and proved the isomorphism by X-ray diffraction studies, in spite of the fact that they possess different cationic compositions. In addition, we successfully prepared complete solid solutions Ba6(Bi1-xEux)9B79O138 (0 ≤ x ≤ 1). Single crystal XRD characterizations on a qualified crystal of BBBO proposed an ordered structure model in the noncentrosymmetric space group R3. It possesses a layered-type structure composed of BO4-BiO6-BO4 sandwiched layers and polyborate inter-layer groups. Ba 2+ atoms locate in the inter-layer cavities. There are three and two independent Bi and Ba atoms, respectively. In other words, we took one more step forward in understanding the structure of REBaB9O16 by analysing its new analogue. It is believed to be helpful for further interpreting and developing REBaB9O16-based optical materials.

Symmetry dependent evolution of the Tb 3+ photoluminescence in Ba 6 ( RE 1−x Tb x ) 9 B 79 O 138 ( RE = La and Y, 0 ≤ x ≤ 1) and Ce 3+ -to-Tb 3+ sensitization effect: A re-visit to RE BaB 9 O 16

“…Please note that the metallic composition of BBBO is different with REBaB 9 O 16 . Indeed, it was suggested in literature that the true composition of "REBaB 9 O 16 " was likely incorrect, which was proved by the formation of Ba 6 Eu 9 B 79 O 138 , showing the same powder X-ray diffraction patterns with REBaB 9 O 16 [18,19]. We are therefore strongly motivated to re-investigate the true composition of this well-known family "REBaB 9 O 16 " and the PL property with the possible new formula, Ba 6 RE 9 B 79 O 138 .…”

“…In literature, the recent publication on the structure determination of BBBO already suggested the formula of "REBaB 9 O 16 " was likely incorrect [18]. The possible reason is due to the over-high annealing temperature (usually > 900 C) when preparing "REBaB 9 O 16 " powder, which is higher than the melting points of BaB 4 O 7 (865 C) and Ba 2 B 10 O 17 (892 C) [22,23].…”

“…2a and b respectively. First, we performed Le Bail fittings on the representative samples, including BLBO, BYBO and the Tb 3þ fully concentrated compound (named as BTBO), using the reported lattice parameters from BBBO (R3, a ¼ 7.841 Å, c ¼ 46.557 Å, and V ¼ 2478.6 Å 3 ) as the initial values [18]. All the refinements gave a good convergence as shown in Fig.…”

“…Such a discrepancy may originate from the really complex structure and the possible slight differences from sample to sample during the preparation processes. This dilemma was released by the recent publication of the structure determination of Ba 6 Bi 9 B 79 O 138 (BBBO), which is proved to be a new member of REBaB 9 O 16 [18]. It possesses a layered-type structure constructed by the alternating stacking of BO 4 eBiO 6 eBO 4 and polyborate layers.…”

Ambient‐Pressure Stabilization of β‐GdB3O6 by Doping with Bi3+ and Color‐Tunable Emissions by Co‐Doping with Tb3+ and Eu3+: The First Photoluminescence Study of a High‐Pressure Polymorph

“…Given the necessity of doping with Bi 3 + ,i tw as an atural idea to take advantage of the sensitization effect of Bi 3 + (i.e. possible Bi 3 + -to-Eu 3 + ,B i 3 + -to-Tb 3 + ,o re ven Tb 3 + -to-Eu 3 + energy transfer) [43][44][45][46] to obtain as ingle-phase color-tunable or white emission phosphor by manipulate the triply doped concentrationso f Bi 3…”