Spectral and structural features of Lu1 − x RE x BO3 compounds

Evolution of Spectral and Structural Characteristics of Orthoborates Lu0.99 – xGdxEu0.01BO3

“…According to X-ray phase analysis, the samples Lu 0.97 Gd 0.02 Eu 0.01 BO 3 (spectrum 1) and Lu 0.84 Gd 0.15 Eu 0.01 BO 3 (spectrum 6) are single-phase and have calcite and vaterite structures in which boron atoms have trigonal and tetrahedral coordination, respectively. In spectrum 1, absorption lines with maxima at 628, 745, 773, and 1236 cm -1 are observed due to vibrations of the B-O bonds in the calcite structure [5,[23][24][25]. In spectrum 6, the 12 Eu 0.01 BO 3 is identical to the spectrum 6, since the sample is also single-phase with a vaterite structure.…”

“…It was shown in [4,5] that synthesized at T = 970-1100°C (the temperature of the existence of the calcite phase of LuBO 3 ) solid solutions consisting of lutetium borate (LuBO 3 ), which, as noted above, has two stable structural modifications (vaterite and calcite) and borates Lu 1 -x RE x O 3 (RE = Eu, Gd, Tb, Dy, and Y), which at x > 0.15-0.2 have only one structural modification, vaterite [17][18][19], crystallize in the vaterite structure. It seems appropriate to study the structural transformations on the surface and in the volume of Lu 1 -x RE x BO 3 microcrystals with an increase in the concentration of RE 3+ .…”

“…The unambiguous correspondence between the luminescence spectra of borates of rare-earth elements and their structural state makes it possible to control the spectral characteristics of borates in a directed way by changing their structure [1][2][3][4][5][6][7][8][9]. Since borates can be used as effective phosphors for LED light sources, the study of methods for directional changes in their spectral characteristics is of considerable interest.…”

“…Significant differences in the luminescence spectra of various structural modifications are observed for borates of rare earth elements doped with Eu 3+ ions. Luminescence spectra of LuBO 3 (Eu) samples having the calcite structure show two narrow bands at λ max = 589.8 and 595.7 nm (electron transition 5 D 0 → 7 F 1 ) [2,4,5]. The luminescence spectrum of the vaterite modification REBO 3 :(Eu), where RE is Lu, Y, or Gd, contains three bands in the following wavelength ranges: 588-596 nm (electron transition 5 D 0 → 7 F 1 ), 608-613 nm, and 624-632 nm ( 5 D 0 → 7 F 2 ) [1,2,4,10].…”

Structural and spectral characteristics of Pr-=SUB=-1-x-=/SUB=-Lu-=SUB=-x-=/SUB=-BO-=SUB=-3-=/SUB=- orthoborates

“…It was shown in [5] that the solid solution Lu 1−x In x BO 3 , consisting of lutetium borate (LuBO 3 ) having two stable structural modifications, vaterite and calcite [6][7][8], and indium borate (InBO 3 ) having only one structural modificationcalcite [9][10][11] synthesized at 780 • C (existence temperature of vaterite LuBO 3 ) with x > 0.08−0.1 crystallizes in the calcite structure. At the same time, Lu 1−x RE x BO 3 solid solutions (RE = Eu, Gd, Tb, Dy and Y), consisting of lutetium borate and REBO 3 , having only one structural modificationvaterite [6][7][8], with x > 0.15−0.2, synthesized at T = 970−1100 • C (existence temperature of calcite phase LuBO 3 ), crystallize in the vaterite structure [12][13][14][15].…”