Applications of light-emitting nanoparticles

• US 6,918,946 B2
• Filed: 03/28/2002
• Issued: 07/19/2005
• Est. Priority Date: 07/02/2001
• Status: Expired due to Term

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Korgel, Brian A., Johnston, Keith P., Thurk, Paul
• Primary Examiner(s): WYSZOMIERSKI, GEORGE P
• Application Number:
  US10/109,608
• Publication Number:
  US 20030034486A1
• Time in Patent Office: 1,209 Days
• Field of Search: 753/62, 753/69, 753/71, 257/13
• US Class Current: 75/362
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C30B 29/605 Products containing multiple oriented crystallites, e.g. columnar crystallites
• CPC Class Codes: C30B 7/00 Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions from molten solvents C30B9/00; by normal or gradient freezing C30B11/00; under a protective fluid C30B27/00
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02535 including tin
• CPC Class Codes: H01L 21/02601 Nanoparticles fullerenes H10K85/211
• CPC Class Codes: H01L 21/02628 using solutions
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/18 within the light emitting region
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/26 Materials of the light emitting region
• CPC Class Codes: H01L 33/34 containing only elements of Group IV of the Periodic Table
• CPC Class Codes: H10K 10/701 Organic molecular electronic devices
• CPC Class Codes: Y10S 977/774 Exhibiting three-dimensional carrier confinement, e.g. quantum dots
• CPC Class Codes: Y10S 977/81 Of specified metal or metal alloy composition
• CPC Class Codes: Y10S 977/95 Electromagnetic energy
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2993 Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]

Abstract

A method for the production of a robust, chemically stable, crystalline, passivated nanoparticle and composition containing the same, that emit light with high efficiencies and size-tunable and excitation energy tunable color. The methods include the thermal degradation of a precursor molecule in the presence of a capping agent at high temperature and elevated pressure. A particular composition prepared by the methods is a passivated silicon nanoparticle composition displaying discrete optical transitions.

Claims

1. A light emitting device, comprising:

a plurality of nanoparticles, the nanoparticles comprising a Group IV metal selected from the group consisting of silicon, germanium and tin and a capping agent coupled to the Group IV metal which inhibits oxidation of the nanoparticles, wherein the nanoparticles have an average particle diameter of between about 1 to about 100 angstroms; and

an anode electrically coupled to the plurality of nanoparticles; and

a cathode electrically coupled to the plurality of nanoparticles;

wherein the anode and cathode together are configured to conduct an applied current to the nanoparticles, wherein the nanoparticles produce light in response to the applied current.

2. The device of claim 1, wherein the anode comprises a transparent conductive oxide.

3. The device of claim 1, wherein the anode comprises a transparent conductive oxide and a supporting substrate, and wherein the transparent conductive oxide is formed on the supporting substrate.

4. The device of claim 1, wherein the anode comprises a transparent conductive oxide and a supporting substrate, and wherein the transparent conductive oxide is formed on the supporting substrate, and wherein the supporting substrate comprises glass.

5. The device of claim 1, further comprising a supporting host, wherein the nanoparticles are positioned in the supporting host.

6. The device of claim 1, further comprising a supporting host, wherein the nanoparticles are positioned in the supporting host, and wherein the supporting host is a polymer.

7. The device of claim 1, wherein at least some of the nanoparticles have an average particle diameter of between about 1 to about 100 angstroms.

8. The device of claim 1, wherein the capping agent inhibits oxidation of the nanoparticles during use.

9. The device of claim 1, wherein the Group IV metal is silicon.

10. The device of claim 1, wherein the Group IV metal is germanium.

11. The device of claim 1, wherein the capping agent is represented by the general formula:

(R)_n—

X wherein X is an atom or functional group capable of binding to the surface of the composition; and

wherein R is hydrogen, an aryl group having between 1 and 10 carbon atoms, or an alkyl group having between 1 and 10 carbon atoms;

n is an integer of at least 1.

12. The device of claim 1, wherein the capping agent is an alcohol.

13. The device of claim 1, wherein the capping agent is an amine.

14. The device of claim 1, wherein the capping agent is a thiol.

15. The device of claim 1, wherein the capping agent is an alkene.

16. The device of claim 1, wherein the capping agent is octanol.

17. The device of claim 1, wherein the Group IV metal consists of silicon.

18. The device of claim 1, wherein the capping agent is CdS.

19. The device of claim 1, wherein the capping agent is ZnS.

20. The device of claim 1, wherein the nanoparticles further comprise a coating.

21. The device of claim 20, wherein the coating is an organometallic coating.

22. The device of claim 1, wherein the Group IV metal consists of germamum.

23. The device of claim 1, wherein the Group IV metal consists of tin.

24. The device of claim 1, wherein the Group IV metal is a mixture of two or more Group IV metals selected from the group consisting of silicon, germanium and tin.

25. The device of claim 1, wherein the capping agent is coupled to the metal by covalent bonding.

26. The device of claim 1, wherein the capping agent is coupled to the metal by hydrogen bonding.

27. The device of claim 1, wherein the capping agent is a mixture of two or more capping agents.

28. The device of claim 1, wherein the capping agent is selected from the group consisting of alcohols, alkenes, alkynes, thiols, ethers, thioethers, phosphines, amines, amides, carboxylates, sulfonates, and quatemary ammomum compounds.

29. The device of claim 1, wherein the nanoparticles further comprise a coating having the same or a different composition as the nanoparticle.

30. The device of claim 29, wherein the coating is organometallic.

31. The device of claim 29, wherein the coating is silicon.

32. The device of claim 1, wherein the nanoparticle is a nanowire.

33. The device of claim 1, wherein the device is not an organic LED.

34. A light emitting device, comprising:

a plurality of nanopartieles, formed by the method comprising heating a mixture of a Group IV organometallic precursor selected from the group consisting of silicon, germanium, and tin precursors and a capping agent at a temperature wherein the precursor decomposes, and the nanoparticles are formed;

an anode electrically coupled to a plurality of nanoparticles; and

a cathode electrically coupled to a plurality of nanoparticles;

wherein the anode and cathode together are configured to conduct an applied current to at least a plurality of the nanoparticles, wherein at least a plurality of the nanoparticles produce light in response to the applied current.

35. The device of claim 34, wherein the anode comprises a transparent conductive oxide.

36. The device of claim 34, wherein the anode comprises a transparent conductive oxide and a supporting substrate, and wherein the transparent conductive oxide is formed on the supporting substrate.

37. The device of claim 34, wherein the anode comprises a transparent conductive oxide and a supporting substrate, and wherein the transparent conductive oxide is formed on the supporting substrate, and wherein the supporting substrate comprises glass.

38. The device of claim 34, further comprising a supporting host, wherein the nanoparticles are positioned in the supporting host.

39. The device of claim 34, further comprising a supporting host, wherein the nanoparticles are positioned in the supporting host, and wherein the supporting host is a polymer.

40. The device of claim 34, wherein the nanoparticles have an average particle diameter of between about 1 to about 100 angstroms.

41. The device of claim 34, wherein the capping agent inhibits oxidation of the nanoparticles during use.

42. The device of claim 34, wherein heating the mixture comprises heating the mixture at a pressure greater than 1 atmosphere.

43. The device of claim 34, wherein the Group IV organometallic precursor is an organosilane compound.

44. The device of claim 34, wherein the Group IV organometallic precursor is an organogermanium compound.

45. The device of claim 34, wherein the Group IV organometallic precursor is an alkylsilane.

46. The device of claim 34, wherein the Group IV organometallic precursor is an arylsilane.

47. The device of claim 34, wherein the Group IV organometallic precursor is tetraethylsilane or diphenylsilane.

48. The device of claim 34, wherein the capping agent is represented by the general formula:

(R)_n—

X wherein X is an atom or functional group capable of binding to the surface of the composition; and

wherein R is hydrogen, an aryl group having between 1 and 10 carbon atoms, or an alkyl group having between 1 and 10 carbon atoms;

n is an integer of at least 1.

49. The device of claim 48, wherein X is selected from the group consisting of nitrogen, carbon, oxygen, sulfur, and phosphorus.

50. The device of claim 48, wherein X is selected from the group consisting of a carboxylate, a sulfonate, an amide, an alkene, an amine, an alcohol, a hydroxyl, a thioether, a phosphate, an alkyne, an ether, and a quaternary ammonium group.

51. The device of claim 34, wherein the capping agent is an alcohol.

52. The device of claim 34, wherein the capping agent is an amine.

53. The device of claim 34, wherein the capping agent is a thiol.

54. The device of claim 34, wherein the capping agent is an alkene.

55. The device of claim 34, wherein the capping agent is octanol.

56. The device of claim 34, wherein the mixture further comprises a solvent.

57. The device of claim 34, wherein the mixture further comprises a solvent, and wherein the solvent is a hydrocarbon.

58. The device of claim 34, wherein the mixture further comprises a solvent, and wherein the solvent is an aromatic hydrocarbon.

59. The device of claim 34, wherein the mixture further comprises a solvent, and wherein the solvent is a non-aromatic hydrocarbon.

60. The device of claim 34, wherein the mixture further comprises a solvent, and wherein the solvent is cyclohexane or hexane.

61. The device of claim 34, wherein the mixture further comprises a solvent, and wherein the method further comprises removing entrained oxygen from the solvent prior to heating the mixture.

62. The device of claim 34, wherein heating the mixture comprises heating the organometallic precursor and the capping agent at a temperature equal to or greater than the supercritical temperature of the capping agent.

63. The device of claim 34, wherein heating the mixture comprises heating the organometallic precursor and the capping agent at a temperature and pressure such that the capping agent is in a supercritical state.

64. The device of claim 34, wherein the mixture further comprises a solvent, and wherein heating the mixture comprises heating the organometallic precursor, the capping agent, and the solvent at a temperature equal to or greater than the supercritical temperature of the solvent.

65. The device of claim 34, wherein the mixture further comprises a solvent, and wherein heating the mixture comprises heating the organometallic precursor, the capping agent, and the solvent at a temperature and pressure such that the solvent is in a supercritical state.

66. The device of claim 34, wherein the method further comprised removing the formed nanoparticles from the unreacted organometallic precursor and capping agent after heating the mixture.

67. The device of claim 34, wherein the method further comprises extracting the formed nanoparticles from the unreacted organometallic precursor and capping agent with a solvent.

68. The device of claim 34, wherein the method further comprises:

extracting the formed nanoparticles from the unreacted organometallic precursor and capping agent with a first solvent;

adding a second solvent to the first solvent to induce aggregation of the nanoparticles.

69. The device of claim 34, wherein the nanoparticle has an average particle diameter of less than about 100 angstroms.

70. The device of claim 34, wherein the nanoparticle has an average particle diameter distribution of between about 1 and 100 angstroms, and wherein the method further comprises subjecting the nanoparticles to a chromatographic process such that particles of different sizes are separated from each other.

71. A light emitting device, comprising:

a plurality of nanoparticles, the nanoparticles comprising a Group IV metal selected from the group consisting of silicon, germanium and tin and a capping agent coupled to the Group IV metal which inhibits oxidation of the nanoparticles, wherein the nanoparticles have an average particle diameter up to about 100 angstroms; and

an anode electrically coupled to the plurality of nanoparticles; and

a cathode electrically coupled to the plurality of nanoparticles;

wherein the anode and cathode together are configured to conduct an applied current to the nanoparticles, wherein the nanoparticles produce light in response to the applied current.