Abstract: In order to study the effect of Na⁺ doping on the luminescence of Ca₂GdNbO₆∶0.03Sm³⁺ phosphors, a series of Ca₂GdNbO₆∶0.03Sm³⁺, xNa⁺ (x=0.01, 0.03, 0.05, 0.07, 0.10; x is mole fraction) phosphors were successfully synthesized by high-temperature solid-state reaction. XRD patterns and the corresponding refinement results show that Na⁺ were successfully doped into Ca₂GdNbO₆∶0.03Sm³⁺ lattices. The luminescent properties of Ca₂GdNbO₆∶0.03Sm³⁺, xNa⁺ phosphors illustrate that the introduction of Na⁺ effectively improves the luminous intensity of Ca₂GdNbO₆∶0.03Sm³⁺ phosphors. Under the 406 nm excitation, the optimum doped concentration of Na⁺ is 5%, as well as the phosphors emit orange-red light with the strongest emission peak at 602 nm (⁴G_5/2→⁶H_7/2). The calculation of the concentration quenching and the thermal stability of Ca₂GdNbO₆∶0.03Sm³⁺, 0.05 Na⁺ host show that the energy transfer in the matrix occurs mainly among the nearest neighbor ions, and the thermal activation energy is 0.119 eV. The calculated color coordinate (0.593 5, 0.404 7) of the phosphors is located in the orange-red region, which is close to the standard (0.666, 0.333) specified by the international commission on illumination, indicating Ca₂GdNbO₆∶0.03Sm³⁺, xNa⁺ phosphors have potential application prospects in the field of white LEDs.

Key words: orange-red phosphor, Ca₂GdNbO₆∶0.03Sm³⁺, xNa⁺, high temperature solid-state reaction, luminescent property, thermal stability, white LED