Light-emitting diode (LED) devices comprising nanocrystals

• US 9,909,062 B2
• Filed: 02/19/2015
• Issued: 03/06/2018
• Est. Priority Date: 03/19/2007
• Status: Active Grant

• Current Assignee: Shoei Chemical Inc.
• Original Assignee: Nanosys Incorporated (Shoei Electronic Materials, Inc.)
• Inventors: Dubrow, Robert S., Chen, Jian, Hardev, Veeral D., Hofler, Hans Jurgen, Lee, Ernest
• Primary Examiner(s): Leong, Nathan T
• Application Number:
  US14/626,764
• Publication Number:
  US 20150259597A1
• Time in Patent Office: 1,111 Days
• Field of Search: None
• CPC Class Codes: B32B 2457/206 Organic displays, e.g. OLED
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/565 with zinc cadmium
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: G02B 1/02 made of crystals, e.g. rock-salt, semi-conductors G02B1/08 takes precedence
• CPC Class Codes: G02B 1/10 Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 6/0041 provided in the bulk of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H05B 33/04 Sealing arrangements , e.g. against humidity
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
• CPC Class Codes: Y10S 977/81 Of specified metal or metal alloy composition
• CPC Class Codes: Y10S 977/834 Optical properties of nanomaterial, e.g. specified transparency, opacity, or index of refraction
• CPC Class Codes: Y10S 977/952 Display
• CPC Class Codes: Y10T 156/10 : Methods of surface bonding and/or assembly therefor

Abstract

The present invention provides light-emitting diode (LED) devices comprises compositions and containers of hermetically sealed luminescent nanocrystals. The present invention also provides displays comprising the LED devices. Suitably, the LED devices are white light LED devices.

Claims

1. A method of preparing a luminescent nanocrystal composite material, the method comprising:

(a) dispersing a plurality of luminescent nanocrystals in a first polymeric material to form a mixture of the luminescent nanocrystals and the first polymeric material;

(b) curing the mixture;

(c) generating a particulate from the cured mixture; and

(d) dispersing the particulate in a second polymeric material to generate the composite material.

2. The method of claim 1, wherein the dispersing in (a) comprises dispersing the luminescent nanocrystals in aminosilicone.

3. The method of claim 1, wherein the dispersing in (a) comprises dispersing luminescent nanocrystals comprising CdSe or ZnS.

4. The method of claim 1, wherein the dispersing, in (a) comprises dispersing luminescent nanocrystals comprising CdSe/ZnS, InP/ZnS, PbSe/PbS, CdSe/CdS, CdTe/CdS, or CdTe/ZnS.

5. The method of claim 1, comprising adding a cross-linker to the mixture prior to the curing in (b).

6. The method of claim 1, wherein the generating a particulate comprises ball milling the cured mixture.

7. The method of claim 1, wherein the generating a particulate comprises grinding the cured mixture.

8. The method of claim 1, wherein the generating a particulate comprises mechanically processing the particulate into a powder.

9. The method of claim 1, further comprising disposing an inorganic layer on the composite material.

10. The method of claim 9, wherein the inorganic layer is disposed after formation of the composite material.

11. The method of claim 9, wherein the inorganic layer is disposed after formation of the composite material, and prior to formation of the composite material into a film.

12. The method of claim 9, wherein the inorganic layer is disposed after formation of the composite material into a film.

13. The method of claim 9, wherein the inorganic layer is disposed on the composite material by atomic layer deposition.

14. The method of claim 13, wherein the inorganic layer comprises AlO₂.

15. The method of claim 13, wherein the inorganic layer comprises SiO₂.

16. The method of claim 1, wherein the composite material has an optical density of about 0.5 to about 0.9 at the blue LED wavelength and a path length of about 50 micron to about 200 micron.

17. The method of claim 1, wherein the luminescent nanocrystals dispersed in the composite material absorb blue light and emit green light and red light.

18. The method of claim 1, wherein the first polymeric material comprises aminosilicone.

19. The method of claim 1, wherein the first polymeric material comprises one or more of poly(vinyl butyral):

poly(vinyl acetate);

epoxies;

urethanes;

silicone and derivatives of silicone, including polyphenylmethylsiloxane, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, fluorinated silicones and vinyl and hydride substituted silicones;

acrylic polymers and copolymers formed from monomers including methylmethacrylate, butylmethacrylate, and laurylmethacrylate;

styrene based polymers; and

polymers that are crosslinked with difunctional monomers including divinylbenzene.

20. The method of claim 18 or 19, wherein the second polymeric material comprises an epoxy or polycarbonate.

21. The method of claim 1, further comprising forming the composite material into a film.

22. The method of claim 1, comprising adding a cross-linker to the mixture prior to the curing in (b).

23. The method of claim 22, wherein the first polymeric material comprises crosslinked aminosilicone.

24. A method of preparing a luminescent nanocrystal composite material, the method comprising:

(a) dispersing a plurality of luminescent nanocrystals in a first polymeric material to form a mixture of the luminescent nanocrystals and the first polymeric material;

(b) curing the mixture;

(c) generating a particulate from the cured mixture;

(d) dispersing the particulate in a second polymeric material to generate the composite material; and

(e) disposing an inorganic layer on the composite material.

25. The method of claim 24, wherein the inorganic layer is disposed after formation of the composite material.

26. The method of claim 24, wherein the inorganic layer is disposed after formation of the composite material, and prior to formation of the composite material into a film.

27. The method of claim 24, wherein the inorganic layer is disposed after formation of the composite material into a film.

28. The method of claim 24, wherein the inorganic layer is disposed on the composite material by atomic layer deposition.

29. The method of claim 28, wherein the inorganic layer comprises AlO₂.

30. The method of claim 28, wherein the inorganic layer comprises SiO₂.

31. The method of claim 24, further comprising forming the composite material into a film.

32. The method of claim 31, farther comprising optically coupling the film to an LED or a light guide so as to provide the down-conversion of light from the LED.