Preparation and properties of novel tungstate SrLa6W10O40: Eu3+ phosphors

Novel tungstate SrLa6-xW10O40: xEu3+ (x = 0, 0.03, 0.06, 0.09, 0.12, 0.15, 0.18, 0.21) red phosphors were prepared by solid state method at 1150 °C by using SrCO3, La2O3, WO3 and Eu2O3 as raw materials. The powders were agglomerated with particles having mostly spheroidal morphology, mean particle size D50 = 12.8 μm and narrow particle size distribution. With the increase of doping amount x, there is no significant difference in the diffraction peak position of the phosphor, but the cell volume of SrLa6W10O40 slowly decreases. The relative strength of diffraction peaks decreases gradually and the half-peak width widens gradually, indicating that the inclusion of Eu3+ ions affects the crystallization of the SrLa6W10O40 matrix. Excitation and emission spectra of the prepared samples were obtained. The optimal doping content has the SrLa5.85W10O4: 0.15Eu3+ phosphor and is characterised with the colour coordinate of (0.652, 0.348), which is closer to the red standard colour (0.67, 0.33) than the near-ultraviolet red phosphor Y2O2S: Eu3+ (0.622, 0.351) used for commercial LED.