Synthesis and photoluminescence properties of Ln3+ (Ln3+ = Sm3+/Eu3+) doped Na2NbAlO5 phosphors

Abstract A series of Ln 3+ (Ln 3+ = Sm 3+ /Eu 3+ ) ions doped Na 2 NbAlO 5 phosphors have been synthesized by solid-state method. Sm 3+ and Eu 3+ ion doped phosphors are characterized by SEM, XRD, EDX, photoluminescence, decay and thermal stability profiles. The Ln 3+ -doped samples are consistent with the pure Na 2 NbAlO 5 phase which were analyzed by the X-ray diffraction result. SEM results showed the homogeneous aggregates and particles size of Sm 3+ (0.6–0.9 µm) and Eu 3+ (0.2–0.3 µm) doped Na 2 NbAlO 5 . From EDX diagram, the samples are consisted of Na, Nb, Al, O and Sm, or Eu elements.With the introduction of Eu 3+ ions, the decay curves of Sm 3+ decreases monotonically, which supports the occurrence of the energy transfer from Sm 3+ to Eu 3+ in Na 2 NbAlO 5 host. The fluorescence lifetime decreases with increasing temperature. The energy transfer mechanisms of Sm 3+ and Eu 3+ doped Na 2 NbAlO 5 have been investigated and can be derived to be electric dipole-dipole and diopole-quadrupole interactions, respectively. In addition, the temperature-dependent emission spectra of Sm 3+ /Eu 3+ doped Na 2 NbAlO 5 phosphors possess superior thermal stability. Under the ultraviolet light, the prepared Na 2- x NbAlO 5 : x Ln 3+ (Ln 3+ = Sm 3+ /Eu 3+ ) phosphors show the characteristic orange (Sm 3+ ), red (Eu 3+ ) emissions respectively. The obtained results suggest that the new Na 2 NbAlO 5 : x Ln 3+ (Ln 3+ = Sm 3+ /Eu 3+ ) phosphors are promising candidates for white light-emitting diodes.