Synthesis and luminescence of Ca9Eu1−xLnx(VO4)7 (Ln = Y, La, Gd, Lu) phosphors

Ca9Eu1−xLnx(VO4)7 (Ln = Y, La, Gd, Lu) red phosphors were synthesized by high temperature solid state method, and the formation mechanism of Ca9Eu1−xLnx(VO4)7 was investigated by XRD and TG–DSC. The efficient excitation band of Ca9Eu(VO4)7 ranges from 200 to 360 nm. Under the excitation of 284 nm, Ca9Eu(VO4)7 shows a typical red emission centered at 616 nm, which was ascribed to 5D0(r)7F2 transition of Eu3+. There exists energy transfer process from VO43− to Eu3+ ions in the Ca9Eu(VO4)7 sample. The influence of Ln3+ (Ln = Y, La, Gd, Lu) ions on the luminescence properties of Ca9Eu1−xLnx(VO4)7 were carefully studied. Temperature dependence luminescence of Ca9Eu(VO4)7 has been measured to determine the thermal stability of as-prepared phosphor.