WO2009021367A1

WO2009021367A1 - A red phosphor powder used for light emitting diode (led) and its preparing method

Info

Publication number: WO2009021367A1
Application number: PCT/CN2007/003248
Authority: WO
Inventors: Rui Li
Original assignee: Rui Li
Priority date: 2007-08-13
Filing date: 2007-11-16
Publication date: 2009-02-19
Also published as: CN101092563A

Abstract

The present invention provides a red phosphor powder used for light emitting diode (LED) and its preparing method, the empirical formula of the phosphor powder is R2-x-yEuxAy(MO4)3 , wherein 0<x≤2, R is one of or mixture of two of Y, Sc, La, Gd, La, when R is mixture, the cations are equivalently substituted and the total mole of the R is constant; A is one or two of Sm, Bi, 0≤y≤0.3, when A is mixture, the cations are equivalently substituted and the total mole of the A is constant; M is one or two of Mo, W; the particle size of the phosphor powder is less than 2 μm, the main emittingpeak is 616 nm, and the synthetic temperature is 650-1000ºC. The red phosphor powder of the present invention has strong exciting absorption at 370-500 nm in the near ultraviolet region and near the blue region, and has high luminous intensity, good color purity and good stability. According to the present invention the red phosphor with high brightness is made by sol-gel method in which citric acid is used as complexing agent, the reacting temperature of the present invention is greatly less than that of the solid phase reaction, and the particle of the phosphor powder is small, homogeneous and quasi-spherical. The phosphor powder has high purity, high quantum efficiency, excellent luminous property and can be applied in light emitting diode LED and fluorescent lamps which will be excited by near ultraviolet light and blue light.

Description

Phosphor for light-emitting diode (LED) and preparation method thereof

The present invention relates to a phosphor for a light-emitting diode (LED), and more particularly to a red phosphor for a light-emitting diode and other preparation methods. Background technique

The semiconductor lighting industry based on light-emitting diodes (LEDs) is rapidly emerging around the world, which has revolutionized the field of traditional lighting. Compared with traditional lighting technology, LEDs have small and effective effects, strong power saving, low pollution, long life, fast response, and maintenance-free. As a colored light source, the power consumption at the same height is only 'normal. 1/8 - 1/10 of incandescent lamps can last for more than 80,000 hours. It is used in a wide range of applications including urban landscape lighting, large curtain displays, traffic lights, LCD backlights, instrumentation indicators, vehicle lighting, aerospace, military, industrial and home, and is moving towards alternative lighting. It is the new generation of light source in the 21st century.

Currently, commercialization of white LEDs includes the use of RGB tri-color chips, blue LHH yellow phosphors, blue LED yellow and red phosphors, and UV LED+RGB phosphors. The use of blue LEDs with yellow phosphors to achieve white light is the easiest of all technologies, and whether it is in terms of cost, lifetime, brightness, and reliability, etc., the color of the white LEDs obtained by this method The driving voltage and the thickness of the phosphor coating change, the color reproduction is poor, the color rendering index is low, and the warm color system cannot be matched. There are two solutions to solve the above problems. The first one is to use a violet or near-ultraviolet (350-410mm) InGaN tube chip to excite three primary color phosphors to realize white LEDs, so that the color reduction and color rendering index of white LEDs will be better. A large increase (Ra > 90), you can also get a low color temperature white LED device, both methods use red phosphor.

At present, the main choice of white LEDs made with purple or near-violet chips BaMgAl, ₀ O ₁₇ :Eu ²⁺ is a blue phosphor, ZnS: Cu+, Al ³⁺ is a green phosphor, and Y ₂ 0 ₂ S:Eu ³⁺ is a red phosphor. However, the luminous efficiency of the red phosphor Y ₂ 0 ₂ S:Eu ³⁺ is only 1/8 of that of the blue and green phosphors. The red phosphor used in the blue LED chip is mostly binary alumina sulfide MS: Eu ²⁺ (M is one or more of alkaline earth metal ions Mg, Ca, Sr, Ba), MS: Eu ²⁺ and Y ₂ 0 ₂ S: The stability of Eu ³⁺ is poor, which seriously affects the lifetime of white LED devices. Therefore, it is necessary to find a red phosphor with strong absorption in the near ultraviolet region and blue region and stable stability. Very necessary. Although there was a patent application for "red phosphor" in the country (application number is 01138060.8, application date is December 27, 2001, publication number is CN1357598A, and publication date is July 10, 2002), the document discloses a Red Phosphor This red phosphor contains MoO ₃ , Eu ₂ 0 ₃ , and also contains one or more of oxides and fluorides of Ca, Sr, Cd, but does not involve tungstate and a new synthesis method. In addition, the applicant of the above patent also applied for another patent of "red phosphor" (application number is 03123790.8, application date is May 21, 2003, publication number is CN1462789A, public day is December 24, 2003) This document discloses a red phosphor A _x B _y C _z _ _2y (M0 ₄ ) ₂ _^ _xy2 : 2D, which contains one or more stalks of Li, Na, Eu, Y, Gd , Lu—one or more, which must have Eu, contain one or more of Mg, C, Sr, and also contain one or more of LiF, NaF, KF, where M is io or W or both The mixture, but not related to tungstate and new synthetic methods. Moreover, the phosphors disclosed in the above two documents are not directed to white light emitting diodes, and they are phosphors for phosphors, displays, televisions, and the like. Patent "a red phosphor for LED and its preparation method and electric light source made" (Application No.: 200310101629.7, Authorization No. CN 1239673C, Authorized Announcement Date: February 1, 2006) LED with red phosphor A _a MO _b :Eu _x , R _y , which must contain Eu, also contains {^,0 51", 8 211, (^ and § one or more, M is Cr, One or more of Mo, W, Nb, Ta, Zr, Hf; R is one or more of Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, Qi and n: Although this patent is directed to a red phosphor for LEDs, the synthesis method is a solid phase method and its composition is different from the present invention.

The luminescent properties of phosphors are greatly influenced by their particle size, shape and particle size distribution, so a suitable preparation method is necessary. At present, the phosphors for synthesizing LEDs mostly adopt the solid phase method. The sample particles obtained by this method are large, the crystal structure is destroyed after ball milling, the luminous efficiency is lowered, the shape is irregular, the particle size distribution range is large, and the synthesis temperature is high. High energy consumption, in line with the energy saving concept of LED Back. When the phosphor is mixed with the epoxy resin or the silica gel slurry, the large particle phosphor has a faster sedimentation rate than the small particle phosphor. After the system is cured, the uneven size and spatial distribution will affect the color of the entire LED. The distribution of the strength, therefore, it is also necessary to develop a phosphor having a small and uniform particle size. Sol-gel technology has low synthesis temperature, small size, uniformity and controllability, and the shape is spherical, which reduces the light scattering of the illuminant and minimizes the irregular shape of the luminescent layer. The phosphor has high resolution and luminous efficiency, which in turn extends the life of the device. Summary of the invention

In view of the deficiencies in the prior art, an object of the present invention is to provide a red phosphor for a light-emitting diode which has strong excitation absorption in a near-ultraviolet region and a blue region of 350 to 500 nm, and has high luminous intensity, and The color purity is high; the present invention also provides a method for preparing the phosphor.

A red phosphor for a light emitting diode having a structural formula of R ₂ . _x — _y Eu _x A _y (M0 ₄ ) ₃ , wherein R is one or two of Sc, Y, La, Gd, Lu, A is one or two of Sm, Bi; M is a mixture of Mo, W or a mixture of both, where 0 <>:<; 2: 0 <x<0.3, x >y, x, y In mole percent. The invention adopts EIJ ³⁺ as an activator, the process is simple, the obtained product particles are small and uniform, the luminescence brightness is high, the color purity is good, and the stability is good; the phosphor disclosed by the invention has strong intensity in the range of 350~500 rim. Excitation absorption, matched with near-ultraviolet and blue LED chips, is a red phosphor for white LEDs. The present invention uses a sol-gel wet chemical method to obtain a red phosphor having a small and uniform particle size and a synthesis temperature lower than that of the conventional solid phase method by 200 to 300 Å, but having a high luminescence intensity. DRAWINGS

Figure 1: Red phosphor

The XRD pattern was burned for 5 h at 900 Torr.

Figure 2: Scanning electron microscopy (SEM) image of the sample obtained by the sol-gel method (a) and the solid phase method (b) at 90 CTC for 5 h.

Figure 3: Phosphor (a) L _ai . ₂ Eu ₀ .8 (Mo04) 3 ₅ 900 ° C; (b) Y^Eu^MoO^, 900 ° C; (c) Yo. ₈ Eu ₁ . ₂ ( Mo0 ₄ ) ₃ , 700'C; (d) Gd ₈ Eu _{1 2} (MoO ₄ ) ₃ , 900 ° C; (e) GdosEu^MoO^, 800Ό excitation (left, λ„=616nm) and emission spectrum (right, A„=395nm, solid line; λ _ei =465nm, dashed line). Detailed ways

The red phosphor of the present invention is a solid solution, and the general formula of the solid solution can be expressed as follows:

2 _-xy Eu _x A _y (MO ₄ )3

Wherein R is one or a mixture of Sc, Y, La, Gd, and Lu. When used in combination, the cation is replaced by an equivalent, and the total number of mole fractions is unchanged; A is Sm, one of Bi Species or two, when used in combination, the cations are equivalently substituted for the sum of their mole fractions; one of Mo, W or a mixture of the two, when used in combination, the total number of mole fractions is unchanged In the above solid solution, 0<x 2, 0 y 0.3, x>y _; wherein x, y are moles.

In the above solid solution R _{2 y} Eu _x A _y (M0 ₄ ) ₃ , a preferred range of x, y is 0.8 x 1.6., 0.02 ^ y ^ O.10;

The above solid solution may also preferably be selected such that R is La, A is Sm, x = L2, and y = 0.03.

Preparation of the red phosphor of the present invention by sol-gel method using citric acid (or EDTA, urea, etc.) as a complexing agent, according to R: Eu: A: M0 ₄ ² - = (2-xy) :x:y:3 stoichiometric ratio R ₂ O ₃ (R is Sc, Y, La, Gd, Lu), Eu ₂ 0 ₃ , R oxide can also be replaced by the corresponding cerium nitrate or carbonate , A oxide or pin acid salt, if one of the raw materials of R, Eu, A is its oxide or carbonate, it should be first dissolved with a strong acid such as 10%-40% nitric acid or hydrochloric acid, on the electric furnace. Continue heating for a period of time to remove excess acid, then add 1.5 to 10 times the number of moles of metal ions

(here, the total moles of Eu and A) of citric acid, then weighed according to the stoichiometric ratio of R: Eu: A: O ₄ ² - = (2-xy): x: y: 3 ( ΝΗ4)6Μο ₇ 0 ₂₄ ·4Η ₂ Ο or tungsten ammonium

(H4 ₀ N ₁₀ O ₄₁ W ₁₂ -xH ₂ O), a transparent solution was prepared by ultrasonic dispersion using NH ₃ , H ₂ 0 or a mass ratio of 1% to 10 °/. The alkaline solution such as NaOH, KOH, Na ₂ C0 ₃ is adjusted to pH 7~8, and kept at 60'C~90'C in an oven or water bath for 24-72 hours. The sample is gradually changed from transparent solution to light brown sol brown yellow gel. Heat up to 100-48 ° C for 12-48 hours to obtain black dry glue. After the crucible, the sample is taken out and baked in an electric furnace, and finally calcined at 450~600'C for 1.5-hour in a high-temperature furnace, and then calcined at 600'C~1100'C for l~10h. A red phosphor sample is required. The invention is further described below in terms of specific embodiments and the accompanying drawings.

Example 1 _:

a molybdate red phosphor which is a solid solution R ₂ _ _x . _y Eu _x A _y (MoO ₄ ) ₃ , wherein R is La, x=0.8, y=0 (ie no A), the solid solution can be expressed as L _ai . ₂ Eu. . ₈ (Mo0 ₄ ) ₃ . Weigh La ₂ O ₃ 0.1278g, Eu ₂ O ₃ 0.0893g _{5 and} dissolve it with 40% hydrochloric acid (volume ratio), continue heating for a while on the electric furnace to remove excess hydrochloric acid, add 0.9567 g of citric acid, (3⁄4) 6Mo ₇ O ₂₄ '4H ₂ 0 0.3449g, ultrasonically dispersed to make a transparent solution, adjusted with ΝΗ ₃ · Η ₂ 0 to adjust ρΗ-7.5, kept in an oven at 60 ° C for 72 hours, heated to 240 ° C for 12 hours , get black dry glue. Then, the black gum was slightly baked on the electrode, carbonized and calcined at 600 ° C for 1 h in a high temperature furnace, and then the sample was calcined at 700 ° C and 900 ° C for 3 h to obtain the desired red phosphor powder. The diffraction patterns prove that they have the same monoclinic structure. Figure 1 shows the XRD pattern of the sample 1^. ₂ £^. ₈ (;\100 ₄ ) ₃ at 900 ° C. The fluorescence spectrum is shown in Figure 3 (a), where the left side is the excitation spectrum (at 395 nm). It has a strong absorption at 465 nm, matching the wavelength of the chip emission of violet and blue GaN-based LEDs, and its emission spectrum on the right, with a main peak at 616 nm.

At the time of preparation, La ₂ O ₃ , Eu ₂ O ₃ may be directly substituted with their nitrates, and may be replaced by carbonates ^; Example 2:

a molybdate red phosphor, which is a solid solution R _{2 y} Eu _x A _y (MoO ₄ ) ₃ , wherein R is Gd, x=0.8, y=0 (ie no A), and the solid solution can be expressed as Gd^EUo .sCMoO ; ^ Take 0.02mol / L of Eu (NO ₃ ) ₃ solution 26ml, 0.01mol L of Gd (N0 ₃ ) ₃ solution 78ml, add citric acid 0.9343 grams, (Ν) ₆ Μο ₇ 0 ₂₄ · 43⁄4Ο 0.3366 g, ultrasonically dispersed to make a transparent solution, adjusted to pH- with ΝΗ ₃ · Η ₂ 0, kept in an oven at 90 ° C for 24 hours, heated to 120 ° C and dried for 24 hours to obtain black 3⁄4 dry glue. Then, the black rubber was slightly baked in an electric furnace, carbonized and calcined at 450 ° C for 5 h in a high temperature furnace, and then the sample was calcined at 900 ° C for 3 h to obtain a desired red phosphor, which is shown in FIG. The RD pattern of the phosphor at 900 ° C, its particle size and morphology were observed by scanning electron microscopy, '' as shown in Figure 2 (a). For comparison, we synthesized the red phosphor Gd _u Eu in this example by solid phase method. ₈ (Mo0 ₄ ) ₃ , Weigh a certain amount of raw materials, Gd ₂ O ₃ 0.5506g, Eu ₂ O ₃ 0.3567g; 'ammonium molybdate 1.3400g, fully grind in agate mortar for 30 minutes, then put corundum After burning at 900 °C for 3 h, a red phosphor was obtained, and its particle size and morphology were observed by scanning electron microscopy, as shown in Fig. 2 (b). By comparison, it can be seen that the phosphor obtained by the sol-gel method has a uniform particle size (about 1-2 μm) and a spherical shape, and the phosphor obtained by the solid phase method has a particle size larger than 10 μm and a very large shape. irregular. Example 3.

A molybdate red phosphor is a solid solution R _{2 y} Eu _x A _y (MoO ₄ ) ₃ , wherein R is Gd, x=1.2, y=0 (ie, no A), and the solid solution can be expressed as Gd ₀ . ₈ Eu _u (MoO ₄ ) ₃ . Take 39ml of 0.02mol TL Eu(N0 ₃ ) ₃ solution, 52ml of 0.01mI L Gd(NO ₃ ) ₃ solution, Al into 0.9343g of citric acid, (ΝΗ4)6Μο ₇ 0 ₂₄ ·4Η ₂ Ο 0.3366g, ultrasonic dispersion A transparent solution was prepared, and ρ 调节 was adjusted with ΝΗ ₃ · Η ₂ 0, kept in an oven at 60 ° C for two days, and heated to 100 ° C for 72 hours to obtain a black dry glue. Then, the black dry glue was slightly baked in an electric furnace, carbonized and calcined at 500 ° C for 3 h in a tempering furnace, and then the samples were respectively calcined at 900 ° C and 800 Torr; 3 h to obtain the desired red phosphor. Their fluorescence spectra are shown in Fig. 3 (d) and (e) respectively. It can be seen from the figure that their fluorescence spectra are different. Their main emission peaks are all at 616am, but the phosphors obtained at 900'C are The relative intensity of luminescence is higher than 800 °C, and there is a shoulder at 626 nm. This is mainly because Gd^Eu^CMoO^ is calcined at 900'C and 800'C. The structure of the desired red phosphor is different. They are orthogonal structures and monoclinic structures, respectively. Example 4:

a molybdate red phosphor, which is a solid solution R _{2 y} Eu _x A _y (MoO ₄ ) ₃ , wherein R is Y, x=0.8, y=0 (ie no A), and the solid solution can be represented as Y _{1 2} Eu ₀₈ (MoO ₄ ) ₃ . Measure 0.02mol L of Eu(N0 ₃ ) ₃ solution into 26ml, 0.01mol/L of Y(N0 ₃ ) ₃ solution 78ml, add 0.9343g of citric acid, (ΝΗ ₄ )5Μο ₇ Ο ₂₄ ·4Η ₂ Ο 0.3366g, Ultrasonic dispersion was made into a transparent solution, and ρΗ-8 was adjusted with ΝΗ ₃ ·3⁄40, and kept in an oven at 60 Torr for two days, and heated to 120 ° C for one day to obtain a black dry glue. Then the black dry glue was slightly baked in an electric furnace, carbonized and calcined in a high temperature furnace at 500 ° C for 3 h, and then the sample was calcined at 900 ° C and 700 ° C for 3 h to obtain the desired red phosphor, Figure 1 The powder diffraction pattern (XRD) of the phosphor obtained at 900 ° C is shown, which shows that it is an orthogonal structure. The fluorescence spectra of the desired red phosphors were obtained by calcination at 900 Γ and 700 ° C for 3 h ^: As shown in Figure 3 (b) and (c), their main emission peaks are all at 616 nm, but the relative fluorescence intensity of the 900 Ό phosphor is higher than 700'C, and there is a shoulder at 626 mn, which is mainly Due to their different structures, the phosphor has a monoclinic structure at 700 Å, which is similar to R=Gd, that is, they have both orthogonal and monoclinic structures. Example 5:

^Molybdate red phosphor, is a solid solution R _{2 y} Eu _x A _y (MoO ₄ ) ₃ , where R is Y and Gd, x=1.6, y=0 (ie no A), the solid solution can be expressed as Ya ₂ Gd ₂ E _Ul . ₆ (Mo0 ₄ ) ₃ . Take 251mol/L of Eu(NO ₃ ) ₃ solution, 53ml, 0.01mol/L 1⁄2 Gd(N0 ₃ ) ₃ solution and 0.01raol L of Y(N0 ₃ ) ₃ solution, each 13.25ml, add urea 0.971:^g , (ΝΗ4)6Μο ₇ 0 ₂₄ ·4Η ₂ 00.3493g, ultrasonically dispersed into a transparent solution, adjusted with Ν3⁄4·3⁄40 to adjust ρΗ 7, kept in an oven at 60 ° C for two days, heated to 120 Ό heat and dry for one day, to get black dry gum. The black dry glue was then slightly calcined on an electric furnace, carbonized and calcined at 500 ° C for 3 h in a high temperature furnace, and then the sample was calcined at 1000 C for 3 h to the desired red phosphor. Example 6:

a molybdate red phosphor, which is a solid solution R ₂ . _x _{y y} Eu _x A _y (MoO ₄ ) ₃ , where x=2, y=0 (ie no A and R), the solid solution can be expressed as Eu ₂ (Mo0 ₄ ) ₃ . Measure 0.02mol/L of Eu(N0 ₃ ) ₃ solution 63.5ml, add 0.9347g of citric acid, (H4)6Mo ₇ O ₂₄ 4H ₂ O 0.3361g, ultrasonically disperse to make a transparent solution, adjust with Ν3⁄4·Η ₂ 0 ρ Η = 7.2, kept in an oven at 60 ° C for two days, heated to 120 ° C and dried for one day to obtain a black dry glue. The black dry glue was then slightly baked on an electric furnace, carbonized and calcined at 500 ° C for 3 h in a high temperature furnace, and then the sample was calcined at 900 Torr for 3 h to obtain the desired red phosphor. Example 7:

A molybdate red phosphor which is a solid solution _y Eu _x A _y (M ₀ O ₄ ) ₃ , wherein R is Sc,

63.2 ml of 0.02 mol L of Eu(NO ₃ ) ₃ solution, 0.32 ml of 0.01 mol/L Sc(NO ₃ ) ₃ solution, 0.9347 g of citric acid, (ΝΗ4)β ο ₇ 0 ₂₄ ·4Η ₂ 0 0.3361 g, Ultrasonic dispersion to make a transparent solution, NH ₃ 3⁄4O was adjusted to pH 7.2, kept in an oven at 60 ° C for two days, and heated to 120 ° C for one day to obtain a black dry glue. The black dry glue was then slightly baked on an electric furnace, carbonized and calcined at 500 ° C for 3 h in a high temperature furnace, and then the sample was calcined at 900 ° C for 3 h to obtain the desired red phosphor. Example 8 _:

A molybdate red phosphor is a solid solution R ₂ _ _x . _y Eu _x A _y (MoO ₄ ) ₃ , wherein R is Lu, x=1.6, y=0 (ie no A), and the solid solution can be expressed as Lu. .4Eu _{1 6} (MoO ₄ ) ₃ . Take 253mol/L of Eu(NO ₃ ) ₃ solution, 53ml, 0.01mol/L of Lu(N0 ₃ ) ₃ solution, 26.5ml, add EDTA 0.9713g, (ΝΗ4)βΜο ₇ 0 ₂₄ ·4Η ₂ 0 0.3493g, Ultra-dispersion is made into a transparent solution, 3⁄4 ΝΗ ₃ · Η ₂ Ο to adjust pH-7, kept in an oven for 60 days at 60 Torr, and heated to 120 ° C for one day to obtain a black dry glue. The black dry glue was then slightly baked on an electric furnace, carbonized and calcined at 500 ° C for 3 h in a high temperature furnace, and then the sample was calcined at 950 Torr for 3 h to obtain the desired red phosphor. Example 9: .

A molybdate red phosphor which is a solid solution _^£8 (11⁄200 ₄ ) ₃ , wherein R is 50% Gd and 50% La, x=1.6, A is Sm, y=0.028, and the solid solution can be expressed For (Gda ₅ Lao. ₅ )

Take 0.02mol/L of Eu(0 ₃ ) ₃ solution 50.8ml, 0.01mol/L Gd(N0 ₃ ) ₃ and La(N0 ₃ ) ₃ solution each 11.8ml, O.Olmol/L Sm (NO ₃ ₃ solution 1.778ml, adding 0.9342g of citric acid, (N3⁄4) ₆ Mo ₇ O ₂₄ -43⁄40 0.3362g, ultrasonically dispersed to make a transparent solution, adjusted with ΝΗ ₃ ·Η ₂ 0

The mixture was incubated at 60 ° C for two days in an oven, and heated to 120 ° C for one day to obtain a black afternoon gel. The black dry glue was then slightly baked on an electric furnace, carbonized and calcined in a high temperature furnace at 500 Torr for 3 h, and then the sample was calcined at 600 ° C for 10 h to obtain the desired red phosphor. Example 10:

- a molybdate red phosphor, a solid solution! ^ ^^ !^. . ^, wherein R is Y, χ = 1.6, Α is Bi, y = 0.3, and the solid solution can be represented by YcuEu, ₆ Bi _a3 (MoO ₄ ) ₃ . Take 0.02mol/L Eu(N0 ₃ ) ₃ solution 50.8ml, O.Olmol/L Y(N0 ₃ ) ₃ solution 6.35π, O.Olmol L Bi(N0 ₃ ) ₃ solution 19.05ml, add lemon Acid 0.9342 g, (Ν3⁄4) ₆ Μο ₇ 0 ₂₄ ·4Η ₂ Ο 0.3362g, Ultrasonic dispersion was made into a transparent solution, pH-7.8 was adjusted with a mass ratio of 1% NaOH, and kept in an oven at 80 ° C for two days, and heated to 180 ° C for one day to obtain a black dry glue. Then the black cognac was slightly baked in an electric furnace, carbonized and calcined at 500 ° C for 3 h in a high temperature furnace, and then the sample was calcined at 1100 Torr for 3 h to obtain the desired red phosphor.

Example 11:

A molybdenum tungstate red phosphor which is a solid solution R _{2 y} Eu _x A _y (Mo0 ₄ ) ₂ (W0 ₄ ) wherein R is 40% of Y and 60% of x=1.2, y=0 (ie no A The solid solution can be represented by (Y _a4 Lao. ₆ ) ₀₈ Eu ₁₂ (MoO ₄ ) ₂ (WO ₄ ). Take 0.02mol/L Eui iO ₃ ) ₃ solution 39ml, 0.01mol/L Y(NO ₃ ) ₃ and La(N0 ₃ ) ₃ solution are 20.8 and 31.2ml respectively, add citric acid, 0.9343g, ( ΝΗ4)6Μο ₇ 0 ₂₄ ·4Η ₂ 00.2245g ₅ 0^ ₀ 0 ₄₁ W ₁₂ ,x3⁄4O 0.1612g Ultrasonic dispersion to make a transparent solution, adjusted to pH=7.6 with 10% by mass of Na ₂ C0 ₃ in an oven 60 Keep it under 'C for two days, heat up to 120'C and keep it dry for one day to get black dry glue. The black dry glue was then slightly baked on an electric furnace, carbonized and calcined at 500 ° C for 3 h in a high temperature furnace, and then the sample was calcined for 5 h to obtain the desired red phosphor. Example 12:

a kind of tungstate red phosphor, which is a solid solution ^ _y Eu _x A _y ( 0 ₄ ) ₃ wherein R is Gd,

Measure 0.02 mol L of Eu(N0 ₃ ) ₃ solution (39 ml), 0.01 mol/L of Gd(N0 ₃ ) ₃ solution (52 ml), and add 0.9343 g of citric acid, 0^. 0 ₄₁ \¥ ₁₂ ,>3⁄40 0.4836g ultrasonic dispersion to make a transparent solution, adjust pH-7.6 with KOH of 5% by mass, keep it in the oven at 60 ° C for two days, heat up to keep dry - day, get black dry. The black dry glue was then slightly baked on an electric furnace, carbonized and calcined at 500 ° C for 3 h in a high temperature furnace, and then the sample was calcined at 900 Torr for 5 h to obtain the desired red phosphor. Example 13:

a molybdate red phosphor, which is a solid solution R ₂ . _x . _y Eu _x A _y (MoO ₄ ;b, where R is La, x=0.8, y=0 (ie no A), the solid solution can be expressed as LauEua^MoO^^ Weigh La ₂ O ₃ 0.1278g, Eu ₂ 0 ₃ 0.0893g, dissolve it with 10 nitric acid (volume ratio), and continue heating for a while on the electric furnace. Time to remove excess hydrochloric acid, add 0.9567 g of citric acid, (Ν) ₆ Μο ₇ 0 ₂₄ ·4Η ₂ Ο 0.34 9g, ultrasonically dispersed to make a transparent solution, adjusted with ΝΗ ₃ · Η ₂ 0 ρ Η = 7.5, 60 烘 in the oven After holding for 72 hours, the temperature was raised to 240 ° C and dried for 12 hours to obtain black dry glue. The black dry glue was then slightly baked on an electric furnace, carbonized and calcined at 600 Torr for 2 h in a high temperature furnace, and then the sample was calcined at 700 ° C and 1000 ° C for 3 h to obtain a desired red phosphor. Example 14:

A molybdate red phosphor is a solid solution R _{2 y} Eu _x A _y (MoO ₄ ; b, wherein R is La, x=0.8, y=0 (ie, no A), and the solid solution can be represented as La _{1 2} Eu ₈ (MoO ₄ ) ₃ . Weigh _3⁄4 1^ ₂ (CO ₃ ) 3 0.1742g, Eu ₂ (CO ₃ ) ₃ -xH ₂ O 0.1228g ₃ Dissolve with 30% nitric acid (volume ratio), in an electric furnace Continue heating for a period of time to remove excess hydrochloric acid, add 0.9567 g of citric acid, (NH4) ₆ Mo ₇ O ₂₄ -4H ₂ 0 0.3449 g, ultrasonically disperse to make a transparent solution, and adjust ρΗ^7.5 with ΝΗ ₃ ·Η ₂ ,, Incubate in an oven at 60 ° C for 72 hours, heat to 240 ° heat and dry for 12 hours, 'get black dry glue. Then black dry glue on the electric stove slightly baked, carbonized and preheated in the oven ' 600 ° C After burning for 2 h, the sample was calcined at 700 ° C and 1000 ° C for 3 h to obtain the desired red phosphor. The above is only a few examples, and those skilled in the art can use other specific examples according to the present invention. The embodiment implements the technical solution of the present invention.

Claims

Claim

A red phosphor for a light-emitting diode having a structural formula of R^ _y E _U A. (M0j ₃ , wherein R is one or two of Sc, Y, La, Gd, Lu, and A is Sm One or two of Bi: M is a mixture of Mo, W or a mixture of both, wherein 0 < x 2, 0^y^0.3, x>y, x, y are mole percent.

2. A phosphor according to claim 1 wherein:

0.8^ ^1.6, 0.02^ ^0.10

The phosphor according to claim 1, wherein R is La, A is Sm, x = 1.2, and y = 0.03.

.4. A method for preparing a red phosphor for a light emitting diode, the method comprising:

U) Mix the raw materials according to the stoichiometric ratio in the structural formula R ₂ - EuA.0i0 such that R: Eu: A: MO " = (2-xy): x: y: 3, 0 < x^2, O^ Y^O.3, x>y, x,y is a mole percentage, wherein the raw material of R is R ₂ O ₃ or its nitrate or its carbonate, and R is one of Sc, Y, La, Gd, Lu Or two or two Eu materials are Eu ₂ O ₃ or lanthanum nitrate or cesium carbonate, and the raw material of A is an oxide or a pin acid salt of A, if the raw material of Eu or / and A is its oxide or carbonate When it is first dissolved in a volume percentage of 10-40% nitric acid or hydrochloric acid, and remove excess acid;

(2) adding 1.5 to 10 times the number of moles of metal ions of citric acid, EDTA or urea to the above mixture, the metal ions including 13⁄4, Eu and A; then 11 _: £11: 8: 1^0 ₄ ² ' = (2): The stoichiometric ratio of :3 is required for weighing (ΝΗ ₄ )6 ο ₇ 0 _Μ · 43⁄40 or

Then ultrasonically dispersed to form a transparent solution;

(3) Adjust the transparent solution to a value of 7~8, 60' (:~~ 90Ό for 24-72 hours, make it a brownish yellow gel, heat up to 100-240 Ό and keep dry for 12-48 hours to get black Dry glue

(4) The black dry glue is baked and calcined at 450~60 (TC for 1-5 hours, then calcined at 60 (TC~1100'C for 1~10h) to obtain the desired red phosphor.

II