Comparative study of the luminescence properties of Ca2+xLa8-x(SiO4)6-x(PO4)xO2:Eu3+ (x = 0, 2) red phosphors

A series of Ca2La8(SiO4)6O2:Eu3+ (CLSO:Eu3+) and Ca4La6(SiO4)4(PO4)2O2:Eu3+ (CLSPO:Eu3+) oxyapatite phosphors have been prepared via traditional solid-state reaction process. The phase composition of phosphors was analyzed by X-ray powder diffraction (XRD), and the morphology was evaluated by scanning electron microscopy (SEM). The characteristic photoluminescence properties were evaluated by analysis of photoluminescence excitation (PLE) and emission (PL) spectra. In addition, the luminescence decay times and emission-temperature relationship were also characterized. The results indicated that the phosphors could be efficiently excited by the near ultraviolet (NUV) light and blue light, and they exhibited red light emission. Meanwhile, the average particle sizes of CLSO and CLSPO hosts are about 2∼8 μm. Moreover, the low symmetry C3 or Cs sites appropriate for Eu3+ in the CLSO and CLSPO hosts are benefit to 5D0 → 7F2 electric dipole transition, which leads to greater R/O values of CLSO:yEu3+ than those of CLSPO:yEu3+. All the obtained results suggested that the prepared phosphors have a potential for application in white light emitting diodes (WLEDs).