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

Sm xY 1-xAl 3(BO 3) 4 polycrystals with huntite structure and glasses of system (mol %) 12.5 (Sm xY 1-x) 2O 3-37.5Al 2O 3-50B 2O 3 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 Sm 3+ 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 × 10 20 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 BO 4 groups of the trigonal BO 3 groups, which are responsible in crystalline Sm xY 1-xAl 3(BO 3) 4 for efficient intracenter non-radiative energy exchange from the metastable excited 4G 5/2 state to phonon excitations.