Effects of scandium substitution on the crystal structure and luminescence properties of LuBO_3: Ce^(3+)

Abstract

The calcite phase of LuBO_3 and ScBO_3 polycrystalline powders were synthesized by solid state reaction method, and the Lu_(1−x)Sc_xBO_3:Ce (x=0.2, 0.5, 0.7) single crystals were grown by the Czochralski method. A large composition deviation between the initial polycrystalline powders and final single crystal was confirmed by electron probe micro-analysis. Raman spectroscopy revealed that moderate lattice disorder was induced by scandium substitution. However, based on the single crystal X-ray study, we finally concluded that the crystal structure of lutetium scandium orthoborate still crystallized in the rhombohedral system belonging to R3^- c. Furthermore, the relationship between the energies of the five 5d levels of Ce^(3+) and the crystalline environment was revealed. The total redshift, total crystal field splitting, and centroid shift of Lu_(1−x)Sc_xBO_3:Ce^(3+) were calculated based on their VUV excitation spectra. The variations trend of these observed spectroscopic parameters was in accordance with the predicted ones.

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