METAL SILICON NITRIDE OR METAL SILICON OXYNITRIDE SUBMICRON PHOSPHOR PARTICLES AND METHODS FOR SYNTHESIZING THESE PHOSPHORS

• US 20110135928A1
• Filed: 09/16/2010
• Published: 06/09/2011
• Est. Priority Date: 03/21/2008
• Status: Abandoned Application

• Current Assignee: Nanogram Corporation (Teijin Limited)
• Original Assignee: Nanogram Corporation (Teijin Limited)
• Inventors: Jaiswal, Abhishek, Ravilisetty, Padmanabha R., Kambe, Nobuyuki, Chiruvolu, Shivkumar
• Application Number:
  US12/883,709
• Publication Number:
  US 20110135928A1
• Time in Patent Office: Days
• US Class Current: 428/402
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3418 Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
• CPC Class Codes: C04B 2235/3427 Silicates other than clay, e.g. water glass
• CPC Class Codes: C04B 2235/3852 Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/3873 Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
• CPC Class Codes: C04B 2235/442 Carbonates
• CPC Class Codes: C04B 2235/444 Halide containing anions, e.g. bromide, iodate, chlorite
• CPC Class Codes: C04B 2235/445 Fluoride containing anions, e.g. fluosilicate
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C04B 35/597 based on silicon oxynitride, e.g. SIALONS
• CPC Class Codes: C04B 35/6265 involving reduction or oxidation
• CPC Class Codes: C04B 35/6268 characterised by the applied pressure or type of atmosphere, e.g. in vacuum, hydrogen or a specific oxygen pressure
• CPC Class Codes: C04B 35/62685 characterised by the order of addition of constituents or additives
• CPC Class Codes: C09K 11/77347 Silicon Nitrides or Silicon Oxynitrides
• CPC Class Codes: C09K 11/77348 : Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: Y10T 428/2982 : Particulate matter [e.g., sphere, flake, etc.]

Abstract

Submicron powders of metal silicon nitrides and metal silicon oxynitrides are synthesized using nanoscale particles of one or more precursor materials using a solid state reaction. For example, nanoscale powders of silicon nitride are useful precursor powders for the synthesis of metal silicon nitride and metal silicon oxynitride submicron powders. Due to the use of the nanoscale precursor materials for the synthesis of the submicron phosphor powders, the product phosphors can have very high internal quantum efficiencies. The phosphor powders can comprise a suitable dopant activator, such as a rare earth metal element dopant.

Claims

1. A collection of crystalline metal silicon nitride/oxynitride particle having an average primary particle diameter of no more than about 250 nm and comprising a dopant activator element at no more than about 10 mole percent relative to the total metal plus silicon molar content, wherein the particles have an IQE of at least about 25%.

2. The collection of crystalline metal silicon nitride/oxynitride particles of claim 1 wherein average primary particle size is no more than about 200 nm.

3. The collection of crystalline metal silicon nitride/oxynitride particles of claim 1 wherein the particles have an IQE value from about 35% to about 75%.

4. The collection of crystalline metal silicon nitride/oxynitride particles wherein of claim 1 the crystalline metal silicon nitride/oxynitride comprise a metal silicon nitride.

5. The collection of crystalline metal silicon nitride/oxynitride particles of claim 1 wherein the crystalline metal silicon nitride/oxynitride comprise a composition represented by the formula L_xSi_yN_{((2/3)x+(4/3)y)}:

R, where L is Mg, Ca, Sr, Ba, Zn or combinations thereof, 0.5≦

x≦

3, 1.5≦

y≦

8 and R is a rare earth activator.

6. The collection of crystalline metal silicon nitride/oxynitride particles of claim 1 wherein the crystalline metal silicon nitride/oxynitride comprises a composition represented by the formula L_1-zMSiN₃:

R_z, where L is a divalent metal element, M is a trivalent metal element, R is a rare earth element and 0.0001≦

z≦

0.1.

7. The collection of crystalline metal silicon nitride/oxynitride particles of claim 1 wherein the crystalline metal silicon nitride/oxynitride particles comprise a metal silicon oxynitride composition.

8. The collection of crystalline metal silicon nitride/oxynitride particles of claim 1 comprises a composition represented by the formula L_xSi_yO_zN_{((2/3)x+(4/3)y+(2/3)z}:

R, where L is Mg, Ca, Sr, Ba, Zn, or a combination thereof, R is a rare earth dopant, 0.5≦

x≦

3, 1.5≦

y≦

8 and 0<

z≦

3.

9. The collection of crystalline metal silicon nitride/oxynitride particles of claim 1 wherein the crystalline metal silicon nitride/oxynitride particles comprise a metal aluminum silicon oxynitride composition.

10. The collection of crystalline metal silicon nitride/oxynitride particles of claim 1 wherein the dopant element comprises a rare earth element.

11. A method for synthesizing metal silicon nitride particles, the method comprising heating a blend of metal nitride precursor particles and silicon nitride precursor particles to form product crystalline metal silicon nitride particles wherein the silicon nitride precursor particles have an average primary particle size of no more than about 100 nm to form product particles having an average primary particle size of no more than about 1 micron.

12. The method of claim 11 wherein the heating is performed at a temperature of no more than about 1600°

C.

13. The method of claim 11 wherein the metal nitride precursor particles have an average primary particle size of no more than about 100 nm.

14. The method of claim 11 wherein the silicon nitride precursor particle have an average primary particle diameter of no more than about 25 nm.

15. The method claim 11 wherein the silicon nitride precursor particles have an average primary particle diameter of no more than about 50 nm and the metal nitride precursor particles have an average primary particle size of no more than about 50 nm.

16. A method for synthesizing metal aluminum silicon oxynitride particles, the method comprising heating a blend of metal composition precursor particles, aluminum composition precursor particles and silicon composition precursor particles to form, product crystalline metal silicon aluminum oxynitride particles, wherein metal composition precursor particles comprise a metal oxide, a metal nitride, a metal oxynitride, a metal carbonate or combinations thereof, the aluminum composition precursor particles comprise Al₂O₃, AlN, AlN_xO_(1-x)3/2 or mixtures thereof, the silicon composition precursor particles comprise Si₃N₄, SiO₂, SiN_(1-x)4/3O_2x or mixtures thereof, wherein the silicon composition precursor particles have an average primary particle size of no more than about 100 nm, and wherein the product metal aluminum silicon oxynitride particles have an average primary particle diameter of no more than about 1 micron.

17. The method of claim 16 wherein the metal composition precursor particles and the aluminum composition precursor particles each have an average primary particle diameter of no more than about 100 nm and wherein the heating is performed at a maximum temperature from about 800°

C. to about 1600°

C. for at least about 15 minutes.

18. The method of claim 16 wherein the precursor particles of each composition have an average particle diameter of no more than 50 nm.

19. The method of claim 16 wherein the aluminum precursor particles comprise Al₂O₃ and the metal precursor composition particles comprise a metal carbonate.

20. A method for synthesizing metal silicon nitride/oxynitride particles, the method comprising heating a blend of metal composition precursor particles and silicon composition precursor particles to form crystalline metal silicon nitride/oxynitride particles, wherein the silicon composition precursor particles comprise Si₃N₄, SiO₂, SiN_(1-x)4/3O_2x, 0<

x<

1 or mixtures thereof and have an average particle diameter of no more than about 100 nm and wherein the metal composition precursor particles comprise a metal oxide, a metal nitride, a metal oxynitride, a metal carbonate or combinations thereof and have an average particle diameter of no more than about 100 nm and the metal silicon nitride/oxynitride product particles have an average particle size of no more than about 1 micron.

21. The method of claim 20 wherein the silicon composition precursor particles have an average particle size of no more than about 50 nm and the metal composition precursor particles have an average particle diameter of no more than about 50 nm.

22. The method of claim 20 wherein the metal composition precursor particles comprise a metal carbonate.