Synthesis And Photoluminescence Properties Of Rare Earth Ions Doped Titanate Phosphors

White light-emitting diodes（LEDs） is a new generation of solid state lighting device because of its high efficiency, small volume, fast response, green, and its also has good resistance of shock, convenient, miniaturization, which promote the application of it. The rare earth doped titanate phosphor is a kind of ideal luminous material because of their chemical stability, low synthesis temperature which have good prospect of application.In this paper, NaGdTiO₄:Sm³⁺ red phosphor, NaLaTiO₄:Eu³⁺ red phosphor, NaLaTiO₄:Dy³⁺ white phosphor were prepared via a solid-state reaction. The crystal structure, morphology and luminescent properties were investigated by X-ray diffraction（XRD）, scanning electron microscope（SEM） and photoluminescence spectra, respectively.A series of NaGdTiO₄:Sm³⁺ red phosphor was synthesized by solid state reaction. The optimum sintering condition was calcinate at temperature of 1000℃ for 4h, the orthorhombic crystal system NaGdTiO₄ was obtained, and the particle size was 2-5μm. The main peak of excitation spectra located at 409 nm. At the same time, it also has good absorption at 460-490 nm. The result indicates that the samples can be excitation effectively by NUV, UV and blue light. When excited at 409 nm, the 567nm( ⁴G₅/2�' ⁶H₅/2), 607nm( ⁴G₅/2�' ⁶H₇/2), 652nm( ⁴G₅/2�' ⁶H₉/2) emissions were obtained, and the 607 nm emission was strongest emission which show a red color. The relationship of PL emission intensity and Sm³⁺ ions content was also researched. When the conten of Sm³⁺ ions was 2.5mol%, the series of Na Gd TiO₄:Sm³⁺ red phosphor get optimal emission effect. Therefore, it was a good phosphor which can be used for the compensatory phosphor of yellow YAG:Ce³⁺ phosphor.A series of NaLa_<sub>1-xTiO₄:xEu³⁺ red phosphor was synthesized by solid state reaction. The optimum sintering condition was calcinate at temperature of 950℃ for 4h, the tetragonal crystal system NaLaTiO₄ was obtained. It has good absorption at 396 nm and 467 nm, which show a good absorption of UV and blue light. When excited at 396 nm, the sample has a strong red emission contain 592nm、619nm and 706 nm originating from typical ⁵D₀�' ⁷FJ（J=1,2,4） electronic transitions of 4f-4f orbit, respectively. The 592 nm and 619 nm emission were strongest emission which show a bright red color. When the conten of Eu³⁺ ions was 30mol%, the series of Na La_1-xTiO₄:x Eu³⁺ red phosphor get strongest emission intensity. The CIE color coordinates of it were（x=0.67,y=0.33）. So, the red phosphor has good potential of application for white LED.A series of NaLa_1-xTiO₄:xDy³⁺ white phosphor was synthesized by solid state reaction. The optimum sintering condition was calcinate at temperature of 950℃ for 4h, the tetragonal crystal system NaLaTiO₄ was obtained. The main peak of emission spectrum located at 389 nm, it also has good absorption at 420-470 nm blue region which can be fit with the emission domain of NUV and blue LED chip. When excited at 389 nm, the sample has white emission contain 486nm、583nm and 663 nm, which originating from the ⁴F₉/2�' ⁶H₁5/2, ⁴F₉/2�' ⁶H₁3/2, ⁴F₉/2�' ⁶H₁1/2 typical emission of Dy³⁺ ions. The ⁴F₉/2�' ⁶H₁5/2 electronic transition at 486 nm emission blue light and the ⁴F₉/2�' ⁶H₁3/2 electronic transition at 583 nm emission yellow light, the mixture of two of them generated white light. When the content of Dy³⁺ ions was 5mol%, the series of La_1-xTiO₄:x Dy³⁺ white phosphor get strongest emission intensity. The CIE color coordinates of it were（x=0.343, y=0.360） which were close to the ideal white light color coordinates（x=0.33,y=0.33）. So, the single martrix white phosphor has good potential application for white LED.