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
  • C09K11/77347—Silicon Nitrides or Silicon Oxynitrides
• • 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
  • C09K11/55—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing beryllium, magnesium, alkali metals or alkaline earth metals
• • 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

Definitions

• the invention is based on a red-emitting phosphor from the class of nitrido-silicates according to the preamble of claim 1.
• the invention further relates to a light source with such a luminous substance and a method for producing the phosphor.
• the light source is in particular a conversion LED.
• Such phosphors are intended in particular for use with white LEDs.
• WO 01/40403 shows a conversion LED in which a
• Conversion LED uses a red-emitting phosphor from the class of nitridosilicates. It is the phosphor MxSiyNz: Eu, where M is Ca,
• the object of the present invention is to provide a red-emitting phosphor, which is characterized by high stability, and therefore can be well used even in a thermally contaminated environment.
• Another 0 task is to use a light source with a phosphor indicate with these properties and specify a method for producing the phosphor.
• the phosphor thus ensures the provision of an efficient, stimulable by blue or ultraviolet light stabilized emitting red phosphor having a dominant wavelength in the range of 600 nm.
• the Eu 2+ -doped alkaline earth nitridosilicates M 2 Si 5 N 8 with M one or more elements from the group Sr, Ca, Ba form a long-known red-emitting phosphor system.
• M one or more elements from the group Sr, Ca, Ba
• M 2 Si 5 N 8 requires M3N2, Si3N 4 and EU2O3 as starting materials.
• a novel stabilized alkaline earth nitridosilicate is obtained if the educt side is at least expanded by SiO 2 .
• the educt side is expanded by SiO2 and additional M3N2.
• the resulting product follows the stoichiometry (1-a) (M 2 Si 5 N 8 : Eu) * a (SiO 2 ), whereby it is preferred that 0 ⁇ a ⁇ 0.25.
• the resulting product follows the stoichiometry (1-a-b) (M 2 Si 5 N 8 IEu) * a (SiO 2 ) * b (M '3N 2), where preferably 0 ⁇ a ⁇ 0.25 and 0 ⁇ b ⁇ 0.30.
• the product does not produce a simple stoichiometry; instead, a product phase diagram based on the three subcomponents SiN4 / 3, SiO2 and MN2 / 3 must be used to describe the product.
• M is more preferably represented by Sr to more than 50 mol%.
• the proportion of the total dopant, in particular here Eu, M should be in the range 0.1 to 15 mol .-%.
• Another or additional dopant such as Ce or Mn is not excluded.
• interesting systems are Eu, Mn on the one hand and Ce, Li (with or without Eu) on the other hand. In the latter case, Li serves the charge compensation.
• the phosphor is particularly suitable for photonic excitation by a light source. These are, for example, lamps such as fluorescent lamps or high-pressure discharge lamps, but in particular also conversion LEDs.
• the phosphor can be used here in particular for the production of white light.
• the RGB principle is used.
• the phosphor according to the invention is used for the red emission.
• another phosphor such as a sion, in particular Ba-sion as known per se, is used.
• the primary radiation of a blue-emitting LED is best suited; a peak wavelength of 410 to 500 nm is preferred.
• a blue phosphor such as BAM may additionally be used.
• the excitation can be effected by the secondary radiation of another phosphor.
• the relative proportions in the phase triangle SiN4 / 3, SiO2, MN2 / 3 are in a range with the following vertices, the sum adding up to 100 mol% in each case:
• Figure 1 is a phase diagram which locates known and novel stabilized nitridosilicates
• FIG. 2 powder diffractogram of a known nitridosilicate Sr2Si5N8: Eu;
• FIG. 4 shows the relative loss of quantum efficiency after oxidation test for the two phosphors of FIGS. 2 and 3;
• Figure 5 shows the result of a stress test under high irradiance for the two phosphors of Figures 2 and 3;
• FIG. 6 shows the measurement of the quenching behavior for the two phosphors from FIGS. 2 and 3 as a function of the temperature
• FIG. 7 shows the excitability of different phosphors as a function of the wavelength
• Figure 8 shows the loss of efficiency of a conversion LED as a function of time.
• FIG. 9 shows a conversion LED in a schematic representation
• Figure 10 shows the converter loss in percent for a stabilized nitride
• FIG. 11 shows the converter loss in percent for an unstabilized nitride
• FIG. 12 shows the spectrum for a stabilized nitride LED
• FIG. 13 shows the spectrum for an LED with unstabilized nitride.
• Embodiments of the novel red-emitting phosphor are as follows.
• the resulting dominant emission wavelength is in the range of 595 to 610 nm.
• M Sr
• the proportion of Eu to M is preferably 0.1 to 15 mol .-%. Preference is therefore given to the - in the phase triangle by the dashed line - exemplary area with the vertices (in brackets is the associated formal stoichiometry indicated):
• the area indicated by the solid line is particularly preferable.
• the rectangle is described here by the following key points:
• the addition of SiO 2 in the batch mixture results in a second phase which is the phosphor wherein D is preferably represented by Eu, significantly improved in terms of all its limiting properties and thereby weakens in any capacity.
• FIG. 7 shows differences in the excitability of the normal and stabilized nitridosilicate.
• the Sr 2 Si 5 N 8 which is unstable in all respects and has a dominant emission wavelength of about 600-610 nm for many applications, can be stabilized in all of the abovementioned aspects (temperature quenching, laser stability, oxidation stability) without losing its optical properties.
• FIG. 2 shows the powder curve for Sr-nitridosilicate Sr 2 Si 5 N 8: Eu as known per se.
• the powder diffractogram of modified SiO 2 stabilized Sr 2 Si 5 N 8: Eu according to FIG. 3 shows completely different peaks.
• FIG. 4 shows the relative loss of quantum efficiency for normal and modified Sr nitridosilicate as in FIGS. 2 and 3.
• FIG. 5 shows the stability for normal and modified Sr nitridosilicate as in FIGS. 2 and 3 under high exposure to laser radiation.
• the duration of the load is indicated as abscissa.
• the ordinate represents the relative intensity of the radiation.
• FIG. 6 shows the temperature quenching for normal and modified Sr nitridosilicate as in FIGS. 2 and 3. where the abscissa is the temperature in degrees Celsius and the ordinate the brightness compared to the brightness at 25 ° C, ie without temperature load.
• FIG. 7 shows the excitability of different phosphors as a function of the wavelength of the excitation.
• Figure 8 shows the loss of conversion efficiency of the stabilized and normal Sr2Si5N8: Eu as a function of time (in hours).
• the abscissa represents the duration of the irradiation.
• the ordinate is the percentage loss.
• a conversion LED 1 has a chip 2 which emits the primary radiation.
• the primary radiation is blue with a peak wavelength in the range 420 to 480 nm, preferably 450 to 470 nm.
• it can also be a UV LED, with the primary radiation generally being in the range 360 to 420 nm ,
• the chip is connected to electrical terminals 3 and a bonding wire 14. It is surrounded by a housing 8, which acts as a reflector 17.
• a potting 5 which contains a phosphor mixture 6 as a dispersion.
• the phosphors are a red-emitting phosphor of the modified nitridosilicate type and a yellow-green phosphor such as YAG: Ce or a sion such as Ba-Si2O2N2: Eu.
• Figure 10 shows an embodiment in which a plurality of LEDs 16 are housed together with an electronic control 17 in a module 15, with a base plate 18 and walls 19.
• the phosphor is mounted here on the inside of the walls or only on the cover plate 20.
• FIG. 13 shows the spectrum of a stabilized nitride LED at the beginning and after aging.
• the stability is significantly higher than the spectrum shown in the comparison, see Figure 14, an LED with non-stabilized nitride.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Luminescent Compositions (AREA)

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Cited By (4)

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Citations (5)

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• 2008
  • 2008-11-20 DE DE102008058295A patent/DE102008058295A1/de not_active Withdrawn
• 2009
  • 2009-10-26 CN CN200980146259.4A patent/CN102216420B/zh not_active Expired - Fee Related
  • 2009-10-26 US US13/130,472 patent/US8896006B2/en active Active
  • 2009-10-26 EP EP09764751A patent/EP2356196B1/de not_active Not-in-force
  • 2009-10-26 JP JP2011536808A patent/JP5254459B2/ja not_active Expired - Fee Related
  • 2009-10-26 WO PCT/EP2009/064072 patent/WO2010057745A1/de active Application Filing
  • 2009-10-26 KR KR1020117014220A patent/KR20110086861A/ko not_active Application Discontinuation
  • 2009-11-04 TW TW098137347A patent/TW201030125A/zh unknown

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