Photoluminescent properties of LiSrxBa1−xPO4:RE3+ (RE = Sm3+, Eu3+) f–f transition phosphors

Rare-earth ions (Sm3+ or Eu3+) doped LiSrxBa1−xPO4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) f–f transition phosphor powders were prepared by a high temperature solid-state reaction. The resulted phosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. The results of XRD indicate that the phase structure of the sample changes from LiBaPO4 to LiSrPO4 when x changes from 0 to 1.0. The excitation spectra indicate that only direct excitation of rare earth ions (Sm3+ or Eu3+) can be observed. The doped rare earth ions show their characteristic emission in LiSrxBa1−xPO4, i.e., Eu3+5D0–7FJ (J = 0, 1, 2, 3, 4), Sm3+4G5/2 → 6HJ (J = 5/2, 7/2, 9/2, 11/2), respectively. The dependence of the emission intensities of the LiSrxBa1−xPO4:Sm3+ and LiSrxBa1−xPO4:Eu3+ phosphors on the x value and Ln3+ (Ln3+ = Sm3+, Eu3+) concentration is also investigated.

► Novel phosphors LiSrxBa1−xPO4: Sm3+ and LiSrxBa1−xPO4: Eu3+ have been synthesized by solid-state reaction method.
► The LiSrxBa1−xPO4: Sm3+ and LiSrxBa1−xPO4: Eu3+ phosphors may be potential f–f transition phosphors used in LED.
► The emission intensity of the LiSrxBa1−xPO4: Sm3+ and LiSrxBa1−xPO4: Eu3+ phosphors can be enhanced by increasing the value of x.