Effect of Gd 3+ , Bi 3+ , or Sm 3+ on luminescent properties of La 2-x MgTiO 6 :xEu 3+ phosphors.

Single phase of Bi3+, Gd3+, Sm3+ and Eu3+ co-doped La2MgTiO6 red phosphors were synthesized by high temperature solid-state method. The phase composition, morphology and fluorescent properties of the phosphors were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrometer. The La2-xMgTiO6:xEu(3+) phosphors can be excited by UV (396 nm) and blue (465 nm) light-emitting diode (LED) chips and show a strong red emitting with dominated wavelength at 615 nm. The optimum doping concentration of Eu3+ ion for La2MgTiO6 is x = 0.5. The luminescent intensities of D-5(0) -> F-7(2) transition of Eu3+ in La1.5-yMgTiO6: 0.5Eu(3+), yBi(3+)/Gd3+/Sm3+ were 1.31 times, 1.32 times and 1.88 times that of La1.5MgTiO6: 0.5Eu(3+) at y = 0.08, 0.06, 0.06 for Bi3+, Gd3+, or Sm3+ sensitizer, respectively. The chromaticity coordinates of La1.44MgTiO6: 0.5Eu(3+), 0.06Sm(3+), (0.6342, 0.3513) were very close to those of the National Television Standard Committee (NTSC) standard red light coordinates.