Spectral asymmetry and deep red photoluminescence in Eu3+-activated Na3YSi3O9 glass ceramics

We report on photoluminescence from Eu3+-activated Na, Y-silicates of the Na3YSi3O9 type. The effect of structural environment on Eu3+-related emission is considered by comparing a glassy reference host to its crystalline correspondents which are obtained through crystallization of the super-cooled melt. Crystallization is accompanied by a quantitative increase in quantum yield and external efficiency of photoluminescence. At the same time, strong Stark splitting of the emission bands and significant changes in the spectral symmetry of photoemission with a notable relative enhancement of the D-5(0) -> F-7(4) relaxation are observed. The results indicate that Eu3+ ions partition on Y3+ lattice sites which undergo changes in coordination, volume and symmetry when moving from glassy to crystalline environment. Potential application of such Eu3+-activated Na3YSi3O9 silicate glass ceramics in light converters is considered. (C)2014 Optical Society of America