Optical properties of non-stoichiometric YAG: Ce luminescent ceramics

Abstract

The aim of this study was to investigate the mutual influence of two factors - deviation from YAG:Ce stoichiometry and vacuum sintering conditions - on the optical and luminescent properties of ceramics. A series of ceramic powders with the general composition formula Y3-хCe0.02Al5+хO12 was synthesized, where −0.024 ≤ x ≤ 0.018 formula units (f.u.) It was demonstrated that deviation from stoichiometry within the specified limits does not affect the morphology, specific surface area, and dispersion composition of ceramic powders. The surface morphology of YAG:Ce ceramic samples with varying stoichiometry was analyzed. The impact of the stoichiometry shift on pore concentration, average grain size, as well as the nature and concentration of impurity phases in ceramics was determined. The influence of the TEOS sintering additive on the grain size and the nature of the macro-defects in ceramics under conditions of stoichiometry shift has been studied. The study of the optical properties of Y3-хCe0.02Al5+хO12 ceramics clearly demonstrates the possibility of creating highly transparent ceramics with an excess of up to 0.018 f.u. of aluminum, while an excess of yttrium significantly reduces the light transmission of the samples. Studies of the luminescent properties have shown that the shift in stoichiometry does not have a significant effect on the luminescence intensity of ceramics, but leads to a shift in the luminescent band maxima and the width of the luminescence bands.