Dy/Sm doped Ca3Si2O4N2 phosphors with high thermal emission stability

Dy3+ and Sm3+ activated Ca3Si2O4N2 samples have been prepared by high temperature solid state reaction, and their luminescence properties were investigated. The excitation spectrum of Ca3Si2O4N2:0.02Dy(3+) monitored at 576 nm has several strong peaks from 340 to 410 nm. Under 365 nm excitation, its emission spectrum exhibits a dominant peak located at about 576 nm with the Commission Internationale de l'Eclairage chromaticity coordinates of (0.395, 0.422) and the correlated color temperature of 3932 K. Sm3+ doped Ca3Si2O4N2 exhibits red emission originating from (4)G(5/2) to H-6(J) (J = 5/2, 7/2, 9/2 and 11/2) transitions, and the charge transfer band of Sm3+ was observed at an unusually low energy of 4.29 eV. As the concentration of Sm3+ increases, the emission intensity of the electric-dipole transition becomes stronger than that of the magnetic-dipole transition, indicating that the local environment of Sm3+ ions becomes more asymmetric. With the increasing temperature, both Sm3+ and Dy3+ doped Ca3Si2O4N2 phosphors exhibit satisfactory thermal stabilities.