Yellow-emitting Ca2Gd(Sb,Nb)O6:Pr3+2 Gd(Sb,Nb)O 6:Pr 3+double-perovskite phosphors excitable by blue-green light

Novel yellow-emitting Ca2Gd(Sb,Nb)O6:Pr3+ 2 Gd(Sb,Nb)O 6 :Pr 3 + phosphors were prepared via a conventional solid-state reaction. Their crystal structure, chemical composition, and photoluminescence (PL) emission properties were comprehensively studied. In this work, the same phase structure (monoclinic in the space group of P 21/c (14) in both Ca2GdSbO6:Pr3+ 2 GdSbO 6 :Pr 3 + and Ca2GdNbO6:Pr3+ 2 GdNbO 6 :Pr 3 + phosphors confirmed that the B ' ' site composition (Sb5+ 5 + and Nb5+) 5 + ) of the Ca2GdB'O6 2 GdB'O 6 double-perovskite structure slightly affected the phase structure while the Pr3+ 3 + was going to substitute the Gd3+ 3 + site. Moreover, the concentration quenching mechanism for both Ca2GdSbO6:Pr3+ 2 GdSbO 6 :Pr 3 + and Ca2GdNbO6:Pr3+ 2 GdNbO 6 :Pr 3 + phosphors was an electric dipole-dipole interaction. The emission spectrum of Ca2GdNbO6:Pr3+ 2 GdNbO 6 :Pr 3 + phosphors appeared to red-shift because of structure distortion. Afterward, the chromaticity coordinates of the optimal Ca2GdSbO6:Pr3+ 2 GdSbO 6 :Pr 3 + and Ca2GdNbO6:Pr3+ 2 GdNbO 6 :Pr 3 + phosphors were determined as (0.462, 0.473) and (0.499, 0.453) in the yellow-emitting region. Finally, under the blue-green (BG) light excitation, the emission intensity, thermal stability, and decay curves of the optimal Ca2GdSbO6:Pr3+ 2 GdSbO 6 :Pr 3 + and Ca2GdNbO6:Pr3+ 2 GdNbO 6 :Pr 3 + phosphors were compared as well.