Synthesis And Luminescence Properties Of Rare Earths Doped Phosphate、Tungsten And Niobate Phosphors

As functional materials, rare earth fluorescent material due to its excellent optical performance, widely used in the LED semiconductor lighting technology, the PDP display technology and other fields. With the development of science and technology and people living standard rise, the fluorescent material performance put forward higher requirements. The emission wavelength of chip from blue to ultraviolet and near ultraviolet area, can provide higher excitation energy for fluorescent material, improve efficiency, this requires a fluorescent material has a high optical performance. The white LED due to its long service life, green environmental protection, energy saving, safe and reliable is known as the new generation of lighting. So the good performance of the LED with fluorescent material has very important practical significance. Research purpose of this paper is to develop novel can be UV LED chip effectively stimulate the three primary colors red, green and blue phosphor white fluorescent powder and a single substrate.In this paper, three kinds of rare earth ions doped phosphors have been synthesized by the solid-state reaction method. The phase composition, structure and luminescence properties were investigated.(1) The single phase phosphors Sr2La2MgW2O12:Eu3+ were synthesized by solid-state reaction method. The study of spectrum indicates that Sr2La2MgW2O12:Eu3+ has strong absorption in UV and blue area. Under 464 nm excitation, the phosphors exhibit the red-orange with a CIE value of (0.626,0.374). The results indicate that Sr2La2MgW2O12:Eu3+ can be excited by blue light and is considered to be potential candidate orange-red phosphors for LED application.(2) The red phosphors Sr4Nb2O9:Eu3+ was synthesized by solid-state reaction method. The study of spectrum indicates that Sr4-xNb2O9:xEu3+ has strong absorption in UV and blue area. Under 393 nm excitation, the phosphors exhibit the red light with a CIE value of (0.6105,0.3902). Sr4-xNb2O9:xEu3+ is considered to be potential candidate red phosphors for LED application.(3) Ba2CaWO6:Dy3+, Eu3+ phosphors with single phase structure were synthesized by high temperature solid state reaction method. The single doped Dy3+ phosphor emits blue white light under 314 nm excitation. It could be seen that the emission spectra of Ba2CaWO6:Dy3+/Eu3+ consisted of blue (Dy3+:4F9/2-6H15/2), yellow (Dy3+:4F9/2-6H]3/2), and the red emission (Eu3+:5D0-7F1 and 5D0-7F2). The results also indicated that it was possible to obtain white light by properly adjusting the doping concentrations of Eu3+and Dy3+.(4) The Ba2CaWO6:Eu3+,Sm3+phosphors were prepared by the traditional solid-state reaction. The phase analysis of phosphor was carried out by XRD patterns and the morphology analysis was carried out by SEM. The spectrum analysis shows that single doped Sm3+ phosphor emit orange light. As compared to the Sm3+ ions single-doped Ba2CaWO6 phosphor, the CIE chromaticity coordinates of the Sm3+/Eu3+ ions co-doped samples shifted towards the red region when the Eu3+ion concentration increased. Therefore, Ba2CaWO6:Sm3+, Eu3+ may be a candidate for the red emitting phosphor.(5) Ba3Y(PO4)3:0.07Dy3+, xEu3+(x=0,0.01,0.03,0.05,0.07,0.09) phosphors with single phase structure were synthesized by high temperature solid state reaction method. The single doped Dy3- phosphor emits blue white light under 393 nm excitation. With the co-doped Eu3+, the phosphor samples showed multicolor emission. With the increase of the concentration of Eu3+ ions, the chromaticity color coordinates can be tuned efficiently from the border of bluish white regions to bluish white region, then to its equal-energy white light point, and eventually to the reddish white region. The results also indicated that we can obtain white light by properly adjusting the doping concentrations of Eu3+ and Dy3+.(6) A series of Ca9Y1-x(PO4)7:xSm3+ phosphor was prepared by conventional solid-state reaction, and their structural and PL properties were studied. The phosphors show a broad excitation band ranging from 350 nm to 500 nm, and can be effectively excited by UV chips. All these characteristics suggest that the orange-red emitting Ca9Y(PO4)7:Sm3+ phosphor can be a suitable red component of phosphor-converted WLEDs.