Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
  • C09K11/7728—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing europium
  • C09K11/77342—Silicates

Definitions

• the invention belongs to the field of luminescent materials, in particular to an orange-red phosphor containing rare earth elements and a preparation method thereof. Background technique
• LED Light Emitting Diode
• the first method is to use red, yellow and/or blue LED chips alone, and the second method is to use ultraviolet or blue light chips in combination with phosphors.
• the most economical and feasible on the market is the use of blue light chips and yellow YAG phosphors for LED lighting, especially LED white light illumination.
• This method is patented by Nichia Corporation (JP 8-198585).
• the white light thus produced is poor in color rendering.
• the current common method is to use a blue chip and two kinds of phosphors, that is, a combination of yellow and orange-red phosphors, or use a blue chip and three kinds of phosphors, namely yellow, orange red and green fluorescent. Powder is used in combination.
• the orange-red phosphor has three kinds of sulfide system, nitrogen (oxygen) system and silicate system.
• the orange-red phosphor of the sulfide system is unstable, releasing toxic gases during decomposition, causing environmental pollution.
• the orange to orange red phosphor of the nitrogen (oxygen) system such as Sr 2 Si 5 N 8 , ( Ca, Sr ) SiAlN 3 , has a complicated preparation method, high equipment requirements, and a relatively high sales price.
• the high price of raw materials is also one of the reasons why LED prices are high and cannot be widely used for civil lighting.
• the orange-red phosphor of the silicate system, the matrix material Si0 2 used for its synthesis is cheap and easy to obtain, and the phosphor material itself is thermally stable, and is one of the preferred packaging raw materials for high color rendering LEDs.
• the Korea Institute of Chemistry discloses an orange-yellow silicate phosphor of the formula Sr 3 _ x Si0 5: Eu 2+ X (CN200480003359.9).
• Intematix implemented an aluminosilicate-based orange-red phosphor (US2007/082492).
• Luo Weihong et al. proposed a silicate yellow-orange yellow phosphor with a cubic garnet structure, Mg 2 Me 2+ a5 Ln 3 Si 2 . 5 0 12 _ 2y N y F y (CN 101255338 A ).
• silicate is used. It is a phosphor material, but because the silicate itself is unstable to acid and water, the silicate is used in the use of LEDs, for example, when using an acidic silicone adhesive for packaging, or under high humidity conditions. It is easy to fail.
• Another object of the invention is to provide a process for preparing the silica coated orange-red phosphor.
• M is one or more selected from the group consisting of Mg, Ca, Ba, Be, Zn, Li
• RE is a combination of Eu ( ⁇ ) or Eu and another rare earth element
• Si0 2 is a phosphor outside
• x, y, z, and w respectively represent values of the following ranges: 0 ⁇ xl, 0 ⁇ y 0.2, lz ll, 0 ⁇ w 0.2.
• the molar ratio of the M is one or more of Mg, Ca, and Ba.
• the RE is Eu ( ⁇ ) or Eu and a combination of one or more selected from the group consisting of Ce, Sm, La, Pr, Tb, Gd, preferably Eu or a combination of Eu and Gd (4L), More preferably Euo
• the preparation method of the silica-coated orange-red phosphor proposed by the invention comprises the steps of:
• step 4) The product after the screening of step 3) is uniformly dispersed in anhydrous ethylene glycol to prepare a suspension, and then nano-SiO 2 is added to the suspension;
• step 5 heating and ultrasonically dispersing the suspension prepared in step 4); 6) solid-liquid separation of the suspension in step 5) to obtain a solid product;
• step 7) The solid product obtained in step 6) is subjected to a burning treatment.
• the reaction flux in the step 1) is one or more of the halides of the element M, and the amount of the reaction flux is 0.05%-10% of the total mass of the raw materials, and the pulverized mixture is The high energy ball mill pulverizes the mixture, and the time for pulverizing the mixture is 0.5-3 hours.
• the temperature of the solid phase reaction in the step 2) is 1000-1300 ° C
• the reaction time is 2-12 hours
• the solid phase reaction is carried out in a reducing atmosphere.
• the screening of the step 3) is to remove particles having a particle diameter of 2 ⁇ m or less in the synthesized product.
• the suspension in the step 4) is a suspension having a mass concentration of the product of 0.5-10%, and the amount of the added nano SiO 2 is 0.5%-5 of the mass of the screened product. %.
• the mass ratio of the silica to the coated powder is 1:20-200.
• the heating and ultrasonic dispersion in the step 5) are heated to 40-70 degrees, ultrasonically dispersed at a constant temperature, and ultrasonically dispersed while stirring at a speed of 200-300 rpm, and the stirring time is 0.5-3 hours.
• the solid-liquid separation method in the step 6) is centrifugal separation, and the solid product is washed with anhydrous ethanol for 2 to 5 times, and then dried, and the drying condition is 90 to 110 degrees, and the drying time is 5-10 hours.
• the burning temperature in the step 7) is 200-350 degrees, and the burning time is 2-12 hours.
• the invention pulverizes the raw materials in advance, and the pulverized raw materials have higher reactivity, and the raw materials are pulverized while being mixed using a high-energy ball mill, and the raw materials are small in volume and uniformly mixed, thereby reducing the synthesis of the high-temperature solid phase synthesis reaction.
• Temperature 1000-1300 degrees
• the phosphor obtained by firing under the above conditions has a small volume and can be directly used, thereby avoiding the post-treatment step of powder pulverization in the conventional production preparation, and effectively avoiding surface damage and brightness loss caused by the pulverization process on the powder;
• the invention coats the surface of the phosphor, and the raw materials used are cheap and easy to obtain.
• the stability of the coated phosphor after the acid and humidity is greatly enhanced;
• the stable silicate orange-red phosphor proposed by the invention can be irradiated under near-ultraviolet blue light Effective excitation, high conversion efficiency, emission wavelength between 575-616nm, can be used in LED packaging, which is beneficial to improve the color rendering of white LEDs.
• FIG. 1 is a phosphor of Example 4 of the present invention (Ba. . . 5 Sr.. 925 Li.. 2 ) 3 Si L1 0 5 : Eu. . . . 7 @Si0 2 excitation emission spectrum (excitation wavelength 460 nm).
• Example 1 The chemical formula of the phosphor in Example 1 ( Ba a04 Sr a94 ) 3 Si0 5 : Eu a06 @SiO 2 , weighed high purity SrC0 3 (41.63 g), BaC0 3 ( 2.37 g), Si0 2 (6.01 g), EuF 3 (1.25 g), and the reaction flux CaF 2 (0.04 g).
• the above mixture is placed in a high-energy ball mill for pulverization and mixing for 40 minutes. After sieving, the mixed raw materials are placed in a high-purity alumina crucible in a reducing atmosphere (3 ⁇ 4 is a 5% by mass ratio of H 2 /N 2 mixed).
• the uncoated phosphor obtained by the above preparation was uniformly dispersed in anhydrous ethylene glycol to prepare a phosphor suspension having a concentration of 5%.
• a phosphor suspension having a concentration of 5%.
• nano-SiO 2 nano-SiO 2
• the amount of SiO 2 used was 2.5% of the mass of the phosphor.
• the suspension was heated to 60 degrees, ultrasonically dispersed at a constant temperature, and stirred at 200-300 rpm for 60 minutes. After a slight precipitation, centrifugation was carried out, and the solid phosphor powder was washed 3 times with an absolute ethanol wash. It is then dried and dried under conditions of 100 degrees for 8 hours.
• the above phosphor semi-finished product was placed in a high-purity alumina crucible and fired at 350 °C for 2 hours to prepare a stable silicate orange-red phosphor having an emission wavelength of 586 nm.
• Example 2 According to the chemical formula of the phosphor in Example 2 (Ba.. 5 Sr.. 925 ) 3 Si0 5 : Eu. . . . 7 @Si0 2 , Weigh high-purity SrC0 3 (40.97 g), BaC0 3 (2.96 g), Si0 2 (6.01 g), EuF 3 (1.46 g), and the reaction flux CaF 2 (0.33 g).
• the above mixture was placed in a high-energy ball mill for pulverization and mixing for 40 minutes. After sieving, the mixed raw materials were placed in a high-purity alumina crucible in a reducing atmosphere (hydrogen was 5% by mass of H 2 /N 2 mixed).
• the uncoated phosphor obtained by the above preparation was uniformly dispersed in anhydrous ethylene glycol to prepare a phosphor suspension having a concentration of 5%.
• a phosphor suspension having a concentration of 5%.
• nano-SiO 2 nano-SiO 2
• the amount of SiO 2 used was 2.5% of the mass of the phosphor.
• the suspension was heated to 60 degrees, ultrasonically dispersed at a constant temperature, and stirred at 200 rpm for 3 hours. After a slight precipitation, centrifugation was carried out, and the solid phosphor powder was washed 3 times with absolute ethanol. It is then dried and dried at 110 degrees for 5 hours.
• the above phosphor semi-finished product was placed in a high-purity alumina crucible and fired at 200 degrees for 12 hours to prepare a stable silicate orange-red phosphor having an emission wavelength of 593 nm.
• Example 3 According to the chemical formula of the phosphor in Example 3 ( Ba ao5 Sr a925 ) 3 Si L1 0 5 : Eu a07 @SiO 2 , high purity SrC0 3 (40.97 g), BaC0 3 ( 2.96 g), Si0 2 ( 6.61 g) were weighed. ), EuF 3 ( 1.46 g), and the reaction flux CaF 2 (0.33 g).
• the above mixture was placed in a high-energy ball mill for pulverization and mixing for 40 minutes. After sieving, the mixed raw materials were placed in a high-purity alumina crucible in a reducing atmosphere (hydrogen was 5% by mass of H 2 /N 2 mixed).
• the uncoated phosphor obtained by the above preparation was uniformly dispersed in anhydrous ethylene glycol to prepare a phosphor suspension having a concentration of 5%.
• a phosphor suspension having a concentration of 5%.
• nano-SiO 2 nano-SiO 2
• the amount of SiO 2 used was 2.5% of the mass of the phosphor.
• the suspension was heated to 60 degrees, ultrasonically dispersed at a constant temperature, and stirred at 300 rpm for 30 minutes. After a slight precipitation, centrifugation was carried out, and the solid phosphor powder was washed 3 times with an absolute ethanol wash. It is then dried and dried under conditions of 100 degrees for 5 hours.
• the above The light powder semi-finished product was placed in a high-purity alumina crucible and fired at 300 degrees for 3 hours to prepare a stable silicate orange-red phosphor having an emission wavelength of 597 nm.
• the uncoated phosphor obtained by the above preparation was uniformly dispersed in anhydrous ethylene glycol to prepare a phosphor suspension having a concentration of 5%.
• a phosphor suspension having a concentration of 5%.
• nano-SiO 2 nano-SiO 2
• the amount of SiO 2 used was 2.5% of the mass of the phosphor.
• the suspension was heated to 60 degrees, ultrasonically dispersed at a constant temperature, and stirred at 280 rpm for 60 minutes. After a slight precipitation, centrifugation was carried out, and the solid phosphor powder was washed 3 times with absolute ethanol. It is then dried and dried under conditions of 100 degrees for 8 hours.
• the above phosphor semi-finished product was placed in a high-purity alumina crucible and fired at 350 °C for 2 hours to prepare a stable silicate orange-red phosphor having an emission wavelength of 601 nm. Its excitation emission spectrum is shown in Figure 1.
• Example 5 According to the chemical formula of the phosphor in Example 5 (Ba 0 . 05 Sr 0 . 925 Li 2 ) 3 (Si 0 . 95 Ge 0 . 05 ) L1 0 5 : Eu 0 .07@SiO 2 , weigh high-purity SrC0 3 (40.97 g), BaC0 3 (2.96 g of), Li 2 C0 3 (0.04 g), SiO 2 (6.28 g of), Ge0 2 (0.58 g), EuF3 3 (1.46 g), and the reaction flux CaF 2 ( 0.055 g). The above mixture was placed in a high-energy ball mill for pulverization and mixing for 40 minutes.
• the mixed raw materials were placed in a high-purity alumina crucible in a reducing atmosphere (hydrogen was 5% by mass of H 2 /N 2 mixed). Gas), kept at 1000 °C for 2 hours, then the temperature was raised to 1250 °C for 5 hours. It was naturally cooled to room temperature, taken out, and subjected to sieving treatment to remove the fine powder ( ⁇ 2 ⁇ m ⁇ ) to obtain the uncoated phosphor material of the present invention.
• the uncoated phosphor obtained by the above preparation is uniformly dispersed in anhydrous ethylene glycol to prepare a concentration It is a 5% phosphor suspension.
• To the suspension was added nano-SiO 2 , and the amount of SiO 2 used was 0.5% by mass of the phosphor.
• the suspension was heated to 60 degrees, ultrasonically dispersed at a constant temperature, and stirred at 250 rpm for 60 minutes. After a slight precipitation, centrifugation was carried out, and the solid phosphor powder was washed 3 times with an absolute ethanol wash. It is then dried and dried under conditions of 100 degrees for 8 hours.
• the above phosphor semi-finished product was placed in a high-purity alumina crucible and fired at 350 degrees for 2 hours to prepare a stable silicate orange-red phosphor having an emission wavelength of 605 nm.
• the above mixture was placed in a high-energy ball mill for pulverization and mixing for 40 minutes. After sieving, the mixed raw materials were placed in a high-purity alumina crucible in a reducing atmosphere (hydrogen was 5% by mass of H 2 /N 2 mixed). Gas), kept at 1000 degrees for 2 hours, then the temperature was raised to 1250 degrees for 5 hours. The mixture was naturally cooled to room temperature, and after being taken out, it was subjected to sieving treatment, and the fine powder ( ⁇ 2 ⁇ m) was removed to obtain an uncoated phosphor material according to the present invention.
• a high-purity alumina crucible in a reducing atmosphere (hydrogen was 5% by mass of H 2 /N 2 mixed). Gas), kept at 1000 degrees for 2 hours, then the temperature was raised to 1250 degrees for 5 hours.
• the mixture was naturally cooled to room temperature, and after being taken out, it was subjected to sieving treatment, and the fine powder ( ⁇ 2 ⁇ m) was removed to obtain an
• the uncoated phosphor obtained by the above preparation was uniformly dispersed in anhydrous ethylene glycol to prepare a phosphor suspension having a concentration of 5%.
• a phosphor suspension having a concentration of 5%.
• nano-SiO 2 nano-SiO 2
• the amount of SiO 2 used was 5% by mass of the phosphor.
• the suspension was heated to 60 degrees, ultrasonically dispersed at a constant temperature, and stirred at 250 rpm for 60 minutes. After a slight precipitation, centrifugation was carried out, and the solid phosphor powder was washed 3 times with an absolute ethanol wash. It is then dried and dried under conditions of 100 degrees for 8 hours.
• the above phosphor semi-finished product was placed in a high-purity alumina crucible and fired at 350 °C for 2 hours to prepare a stable silicate orange-red phosphor having an emission wavelength of 607 nm.
• the present invention discloses a silica-coated orange-red phosphor.
• the stabilized silicate orange-red phosphor disclosed by the invention can be effectively excited under near-ultraviolet blue light irradiation, has high conversion efficiency, and has an emission wavelength of between 575 and 616 nm, and can be used for LED packaging, which is beneficial to improving white LED Color rendering.
• the present invention also provides a method of preparing the orange-red phosphor.
• the method of the invention preliminarily pulverizes the raw material, and the pulverized raw material has higher reactivity, thereby lowering the synthesis temperature (1000-1300 degrees) of the high-temperature solid phase synthesis reaction, and reducing energy consumption and equipment requirements;
• the surface of the phosphor is coated, and the raw materials used are cheap and easy to obtain.
• the stability of the coated phosphor after acid and humidity is greatly enhanced. From the above advantages, the method has good industrial applicability.

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• 2012
  • 2012-05-28 CN CN201210170585.2A patent/CN102660281B/zh not_active Expired - Fee Related
  • 2012-07-13 WO PCT/CN2012/078621 patent/WO2013177848A1/fr not_active Ceased

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