Photo-induced luminescence degradation in Ce, Yb co-doped yttrium aluminum garnet phosphors

Photon-induced luminescence degradation of Ce, Yb co-doped yttrium aluminum garnet phosphors with different Yb concentrations under 457 nm irradiation is studied for the first time, to the best of our knowledge. The degradation behavior is more significant in nano-phosphors prepared via the solgel method, compared with bulkier samples prepared via solid-state reaction. Photoluminescence intensity of Ce³⁺ ions experiences a drop after initial illumination, due to photoionization of Ce³⁺ ions, whereas the down-converted luminescence of Yb³⁺ ions remains relatively stable. Co-doping Yb³⁺ contributes to the luminescence drop of Ce³⁺ with the excessive Yb³⁺ ions serving as additional electron traps. The results are in support of a charge transfer process.