Semiconductor Nanoparticle-Based Materials

• US 20110068322A1
• Filed: 09/23/2010
• Published: 03/24/2011
• Est. Priority Date: 09/23/2009
• Status: Active Grant

• Current Assignee: Nanoco Technologies Limited (Nanoco Group Plc)
• Original Assignee: Nanoco Technologies Limited (Nanoco Group Plc)
• Inventors: Naasani, Imad, Harris, James, Pickett, Nigel
• Granted Patent: US 8,957,401 B2
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• 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 11/70 containing phosphorus
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: H01L 2933/0025 relating to coatings
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil

Abstract

In various embodiments, the present invention relates to a plurality of coated primary particles, each primary particle including a primary matrix material and containing a population of semiconductor nanoparticles, wherein each primary particle is provided with a separate layer of a surface coating material. Various methods of preparing such particles are described. Composite materials and light-emitting devices incorporating such primary particles are also described.

Claims

1. A plurality of coated primary particles, each primary particle comprising a primary matrix material and containing a population of semiconductor nanoparticles,

wherein (i) each primary particle is provided with a separate layer of a surface coating material, (ii) said primary particles are provided in the form of microbeads, and (iii) the surface coating material comprises a polymeric material.

2. A plurality of coated primary particles according to claim 1, wherein said microbeads possess an average diameter of around 20 nm to around 0.5 mm.

3. A plurality of coated primary particles according to claim 1, wherein said primary matrix material comprises a material selected from the group consisting of a polymer, a resin, a monolith, a glass, a sol gel, an epoxy, a silicone, and a (meth)acrylate.

4. A plurality of coated primary particles according to claim 1, wherein said surface coating material comprises a material providing each primary particle with a protective barrier to prevent the passage or diffusion of potentially deleterious species from the external environment through the primary matrix material to the semiconductor nanoparticles.

5. A plurality of coated primary particles according to claim 1, wherein the surface coating material is a barrier that hinders or prevents the passage of oxygen or an oxidising agent through the primary matrix material.

6. A plurality of coated primary particles according to claim 1, wherein the surface coating material is a barrier that hinders or prevents the passage of free radical species through the primary matrix material.

7. A plurality of coated primary particles according to claim 1, wherein the surface coating material is a barrier that hinders or prevents moisture passing through the primary matrix material.

8. A plurality of coated primary particles according to claim 1, wherein the surface coating material possesses a thickness of up to around 500 nm.

9. A plurality of coated primary particles according to claim 1, wherein the surface coating material possesses a thickness of around 5 to 100 nm.

13. A plurality of coated primary particles according to claim 1, wherein the polymeric material is a saturated or unsaturated hydrocarbon polymer, or is a polymer incorporating one or more heteroatoms or heteroatom-containing functional groups.

14. A plurality of coated primary particles according to claim 1, wherein the polymeric material comprises a material selected from the group consisting of an acrylate polymer, epoxide, polyamide, polyimide, polyester, polycarbonate, polythioether, polyacrylonitryl, polydiene, polystyrene polybutadiene copolymer, pyrelene, a silica-acrylate hybrid, polyetheretherketone, polyvinylidene fluoride, polydivinyl benzene, polyethylene, polypropylene, polyethylene terephthalate, polyisobutylene, polyisoprene, cellulose derivatives, and combinations thereof.

15. A plurality of coated primary particles according to claim 1 or 10, wherein said semiconductor nanoparticles contain ions selected from groups 11, 12, 13, 14, 15 and/or 16 of the periodic table, or one or more types of transition metal ion or d-block metal ion.

16. A composite material incorporating a plurality of coated primary particles according to claim 1 or 10 dispersed within a secondary matrix material.

17. A composite material according to claim 16, wherein said secondary matrix material comprises a material selected from the group consisting of a polymer, a resin, a monolith, a glass, a sol gel, an epoxy, a silicone, and a (meth)acrylate.

18. A composite material according to claim 16, wherein (i) said secondary matrix material is in the form of one or more secondary particles, and (ii) a surface of the or each secondary particle is provided with a separate layer of a further surface coating material.

19. A composite material according to claim 18, wherein said further surface coating material comprises a material that provides the or each secondary particle with a protective barrier to prevent the passage or diffusion of potentially deleterious species from the external environment through the secondary matrix material to the primary matrix material.

20. A light-emitting device including a primary light source in optical communication with a formulation comprising a plurality of coated primary particles according to claim 1 or 10 embedded in a host light-emitting diode encapsulation medium.

21. A light-emitting device including a primary light source in optical communication with a formulation comprising a composite material according to claim 16 embedded in a host light-emitting diode encapsulation medium.

10. A plurality of coated primary particles, each primary particle comprising a primary matrix material and containing a population of semiconductor nanoparticles,

wherein (i) each primary particle is provided with a separate layer of a surface coating material, (ii) said primary particles are provided in the form of microbeads, and (iii) the surface coating material comprises an inorganic material.

11. A plurality of coated primary particles according to claim 10, wherein the inorganic material is selected from the group consisting of a dielectric, a metal oxide, a metal nitride, and a silica-based material.

12. A plurality of coated primary particles according to claim 10, wherein the inorganic material is a metal oxide comprising oxide ions and one or more types of metal ion selected from group 2, 13, 14 or 15 of the periodic table, the transition metals, the d-block metals, or the lanthanide metals.

22. A method for preparing a plurality of coated primary particles, each primary particle comprising a primary matrix material and containing a population of semiconductor nanoparticles, the method comprising:

providing each of said primary particles with a separate layer of a surface coating material.

23. A method according to claim 22, wherein the surface coating is provided separately on each primary particle by a chemical deposition technique.

24. A method according to claim 23, wherein said technique is atomic layer deposition.

25. A method according to claim 24, wherein said atomic layer deposition process employs a reaction temperature of around 100 to 500°

C.

26. A method according to claim 24, where said atomic layer deposition process is controlled to provide a surface coating layer thickness of around 1 to 500 nm.

27. A method according to claim 24, wherein said atomic layer deposition process employs a metal precursor and an oxide precursor to deposit one or more layers of a metal oxide on a surface of the primary particles.

28. A method according to claim 22, wherein the surface coating is produced in-situ on a surface of each primary particle.

29. A method according to claim 28, wherein producing the surface coating comprises contacting said surface of each primary particle with one or more polymerisable monomers and subsequently polymerising said monomer(s) on the surface of each primary particle to produce a separate polymeric surface coating on each primary particle.

30. A method according to claim 29, wherein contacting of the primary particles by the polymerisable monomer(s) is effected by dispersing the primary particles within a monomer mixture, optionally including a crosslinking agent and/or polymerisation initiator, and subsequently effecting polymerisation of the monomer(s).