(3 + 1)-Dimensional commensurately modulated structure and photoluminescence properties of diborate KSbOB₂O₅

Abstract

Single-crystal diborate KSbOB2O5 has been prepared under a high temperature molten-salt method and its structure has been determined by single crystal X-ray diffraction analysis. The diffraction pattern shows strong main reflections and weak satellite reflections, clearly indicating a modulated structure. Using the four-dimensional superspace formalism for aperiodic structures, its reflections could be indexed as orthorhombic superspace group Pmn2₁(0β0)s00 with the modulation vector q = 5/12b*, and then the structure solution and refinement reached a final commensurately modulated model that was refined extremely well and did not show any unusual features. On the other hand, the powder sample of KSbOB2O5 was synthesized by the high-temperature solid-state reaction method, and the powder X-ray diffraction pattern fits very well with the simulated from the single-crystal data. In addition, photoluminescence properties of diborate KSbOB2O5 activated by 4.5 mol% Dy(3+) have been studied, indicating an extraordinary phenomenon that the red emission at around 635 nm ((4)F(9/2) → (6)H(11/2)) is much stronger than the yellow emission at around 581 nm ((4)F(9/2) → (6)H(13/2)).

An Unprecedented Antimony(III) Borate with Strong Linear and Nonlinear Optical Responses

“…As early as 1999, Gopalakrishnan and co‐authors reported the first antimony borate RbSbOB 2 O 5 . Subsequently, scientists synthesized a series of antimony borates by high‐temperature reactions in open system, such as K 3 Sb 4 BO 13 , KSbB 2 O 6 , BaSb 2 B 4 O 12 , KSbOB 2 O 5 , and β‐RbSbB 2 O 6 , A 2 SbB 3 O 8 (A=Na, K, Rb), and LnBSb 2 O 8 (Ln=Sm, Eu, Gd, Tb) . Our group also made continuous investigations on the Sb−B−O system and reported a new antimony borate K 2 SbB 3 O 8 in 2016 .…”

Structure modulations in nonlinear optical (NLO) materials Cs2TB4O9(T= Ge, Si)

“…The modulated structures of Cs 2 TB 4 O 9 (T = Ge and Si) are very different from the former two modulated borates AMOB 2 O 5 (A = K, Rb, Cs, Tl; M = Nb, Ta, Sb; Schmid et al, 2000;Schmid & Wagner, 2005;Zhao et al, 2015) and Lu 4 Al-Cu 2 B 9 O 23 (Bolotina et al, 2013). In AMOB 2 O 5 , the structure modulations are caused by the size of the A cation.…”

“…Although the structures of aperiodic crystals have been widely reported for the last few decades, there are only two families among borates: AMOB 2 O 5 (A = K, Rb, Cs, Tl; M = Nb, Ta, Sb; Schmid et al, 2000, Zhao et al, 2015 and Lu 4 Al-Cu 2 B 9 O 23 (Bolotina et al, 2013). In borates, these BO x (x = 3, 4) basic units are more likely to be connected by a common vertex rather than by edges.…”

Crystal structure and luminescence properties of self-activated phosphor CsDyP 2 O 7

“…6 H 15/2 transition and yellow (575 nm) region corresponding to the 4 F 9/2 ! 6 H 13/2 [6,7]. Therefore, it is possible to obtain white luminescence with only Dy 3+ activated phosphors having suitable yellow/blue intensity ratio.…”