Preparation of La3+-doped Sr2GdSbO6: 0.2Eu3+ phosphors and enhancement of luminescence performance

A novel double perovskite-structured phosphor Sr 2 Eu 0.2 Gd 0.8-x SbO 6 : x La 3+ (SEGSO: x La 3+ ) was designed and prepared by conventional high-temperature solid-phase reaction. The effects of doping La 3+ on the crystal structure and luminescence properties of Sr 2 Gd 0.8 SbO 6 :0.2Eu 3+ (SEGSO) phosphors were systematically discussed. It is proved that the phosphor lattice becomes larger, the lattice symmetry decreases, and the band gap narrows after La 3+ replaces Gd 3+ , which ultimately significantly enhances the luminescence intensity. Due to the rigid network structure of the double perovskite structure, the SEGSO: 0.8La 3+ phosphor exhibits excellent thermal stability. In comparison to the undoped La 3+ phosphor, it retains 85 % of its initial emission intensity at 423 K. The phosphors were also evaluated for their potential application in LED lighting by applying two encapsulation methods.