Spectroscopic properties of Sm-containing yttrium-aluminoborate glasses and analogous huntite-like polycrystals

SmxY1–xAl3(BO3)4 polycrystals with huntite structure and glasses of system (mol %) 12.5 (SmxY1–x)2O3–37.5Al2O3–50B2O3 with identical composition have been synthesized by solid state reaction and by melting process, respectively in order to compare light-emission and nonradiative energy transfer mechanisms in the two systems. The data have been analyzed to determine the concentration-dependent quantum yield of the Sm3+ luminescence as well as multipolarity and macro- and microparameters of the Sm–Sm interaction. The results show that the structure of the huntite cation lattice is preserved by passing from polycrystals to glasses, with an increase in the Sm–Sm minimum distance from 0.59 to 0.67 nm. At activator concentration ≤1 × 1020 cm−3, the luminescence quantum yield in glass is higher than in polycrystals. The result turns out to be related to the partial substitution in glass by BO4 groups of the trigonal BO3 groups, which are responsible in crystalline SmxY1–xAl3(BO3)4 for efficient intracenter non-radiative energy exchange from the metastable excited 4G5/2 state to phonon excitations.