Crystal structure evolution and luminescence property of Ce3+-doped Y2O3-Al2O3-Sc2O3 ternary ceramics

Ce3+-doped Y2O3-Al2O3-Sc2O3 ternary ceramics with varying Sc2O3 were prepared via solid-state-reactive method. Their constitutions, crystal structures, microstructures and luminescence properties were thoroughly investigated by powder X-ray diffraction, Sc-45 and Al-27 solid-state nuclear magnetic resonance (NMR), scanning electron microscope (SEM) as well as photoluminescence (PL) characterizations. Single-phased YSAG transparent ceramics with garnet structure and homogeneous microstructures can be obtained. The NMR results suggest that partial [AlO6] octahedrons are converted into [AlO4] tetrahedrons with increased Sc3+ . Partial Sc3+ occupies the remaining octahedral sites, the other Sc3+ occupies the dodecahedral sites. The luminescence spectra of the as-prepared ceramics show broadened emission bands with excessive Sc3+. incorporation. More significantly, the solubility of Ce3+ in garnet ceramics extensively increases due to the incorporation of Sc3+, leading to a considerable red-shift and broadening of emission spectra with little luminescence decline, indicating that the new ceramic phosphors are promising for white-light illumination with improved color rendering index.