Luminescent and thermal properties of novel orange-red emitting Ca2MgTeO6:Sm3+ phosphors for white LEDs

Abstract Novel Sm3+-doped double perovskite Ca2MgTeO6 orange-red emitting phosphors were prepared using solid-state reaction at 1100 °C. The powder phase purity, particle morphology and size, elemental composition, and luminescence properties of prepared samples were analyzed in detail. Under the 405 nm excitation, Ca2MgTeO6:Sm3+ phosphors showed four sharp emission peaks ascribed to the 4f-4f transitions, and the strongest one was at 645 nm. The best doping concentration of Sm3+ in Ca2MgTeO6:Sm3+ phosphors was 0.05 mol. The critical distance of the energy transfer between the Sm3+ ions was calculated to be 16.4 A. The luminescence quenching was confirmed by the dipole-dipole interaction of among Sm3+ ions. The phosphor exhibited excellent thermal stability with high activation energy (0.32 eV). The commission international de l'Eclairage (CIE) chromaticity coordinates of Ca2MgTeO6:Sm3+ phosphors were in the orange-red region. The fabricated white light-emitting diode (w-LED) presented high color rendering index (Ra) of 90 and a good correlated color temperature (CCT) of 6726 K. Thus, Ca2MgTeO6:Sm3+ phosphors have great potential applications in displays and photonic devices.