HIGH QUALITY COLLOIDAL NANOCRYSTALS AND METHODS OF PREPARING THE SAME IN NON-COORDINATING SOLVENTS

• US 20060130741A1
• Filed: 07/30/2002
• Published: 06/22/2006
• Est. Priority Date: 07/30/2001
• Status: Active Grant

• Current Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Original Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Inventors: Yu, Weiyong, Peng, Xiaogang, Battaglia, David
• Granted Patent: US 7,105,051 B2
• Time in Patent Office: Days
• US Class Current: 117/68
• CPC Class Codes: C30B 29/40 AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
• CPC Class Codes: C30B 29/48 AIIBVI compounds wherein A is Zn, Cd or Hg, and B is S, Se or Te
• CPC Class Codes: C30B 29/605 Products containing multiple oriented crystallites, e.g. columnar crystallites
• CPC Class Codes: C30B 5/00 Single-crystal growth from gels under a protective fluid C30B27/00
• 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: G01N 15/0205 by optical means
• CPC Class Codes: G01N 2015/0038 Investigating nanoparticles

Abstract

The present invention provides substantially monodisperse colloidal nanocrystals and new preparative methods for the synthesis of substantially monodisperse colloidal nanocrystals. These synthetic methods afford the ability to tune nanocrystal size and size distribution. By using non-coordinating solvents in the synthetic process, these procedures constitute easier, less expensive, safer, and more environmentally “green” methods than those currently in use. This invention is generally applicable to any II-VI or III-V semiconductor material, and may be useful in generating metal-nonmetal compounds involving transition metals as well.

Claims

1. A composition comprising colloidal nanocrystals, wherein the as-prepared nanocrystals luminesce from about 500 nm to about 700 nm and exhibit a photoluminescence quantum yield up to about 60%.

2. The composition of claim 1, wherein the full width at half maximum of the photoluminescence emission line of the nanocrystals is from about 18 nm to about 25 nm.

3. The composition of claim 1, wherein the full width at half maximum of the photoluminescence emission line of the nanocrystals is from about 22 nm to about 24 nm.

4. The composition of claim 1, wherein the average size of the nanocrystals is from about 1 nm to about 6 nm.

5. The composition of claim 1, wherein the average size of the nanocrystals is from about 4 nm to about 5 nm.

6. The composition of claim 1, wherein the nanocrystals are substantially monodisperse dots, rods, or branched shapes.

7. A light-emitting diode comprising the composition of claim 1.

8. A biological labeling agent comprising the composition of claim 1.

9. A photoelectric device comprising the composition of claim 1.

10. A solar cell comprising the composition of claim 1.

11. A catalyst comprising the composition of claim 1.

12. A laser comprising the composition of claim 1.

13. A substantially monodisperse sample of colloidal nanocrystals produced by a method comprising:

a) combining a cation precursor, a ligand, and a non-coordinating solvent to form a cation-ligand complex; and

b) admixing an anion precursor with the cation-ligand complex at a temperature sufficient to form nanocrystals.

14. A light emitting diode comprising the composition of claim 13.

15. A biological labeling agent comprising the composition of claim 13.

16. A photoelectric device comprising the composition of claim 13.

17. A solar cell comprising the composition of claim 13.

18. A catalyst comprising the composition of claim 13.

19. A laser comprising the composition of claim 13.

21. A light emitting diode comprising the composition of claim 13.

22. A biological labeling agent comprising the composition of claim 13.

23. A photoelectric device comprising the composition of claim 13.

24. A solar cell comprising the composition of claim 13.

25. A catalyst comprising the composition of claim 13.

26. A laser comprising the composition of claim 13.

20. A substantially monodisperse sample of colloidal nanocrystals produced by a method comprising:

a) combining a cation precursor, a ligand, and a non-coordinating solvent to form a cation-ligand complex;

b) admixing an anion precursor with the cation-ligand complex at a first temperature sufficient to induce reaction between the cation-ligand complex and the anion precursor; and

c) adjusting the temperature of the mixture to a second temperature sufficient to form nanocrystals of the reaction product.

27. A method of synthesizing colloidal nanocrystals, comprising:

a) combining a cation precursor, a ligand, and a non-coordinating solvent to form a cation-ligand complex; and

b) admixing an anion precursor with the cation-ligand complex at a temperature sufficient to form nanocrystals.

28. The method of claim 27, wherein the cation precursor comprises a compound of a group II metal, a group III metal, a group IV metal, or a transition metal.

29. The method of claim 28, wherein the group II metal is selected from Zn, Cd, or Hg.

30. The method of claim 28, wherein the group III metal is selected from Al, Ga, or In.

31. The method of claim 28, wherein the group IV metal is selected from Ge, Sn or Pb.

32. The method of claim 27, wherein the cation precursor comprises a metal oxide, a metal carbonate, a metal bicarbonate, a metal sulfate, a metal sulfite, a metal phosphate, a metal phosphite, a metal halide, a metal carboxylate, a metal alkoxide, a metal thiolate, a metal amide, a metal imide, a metal alkyl, a metal aryl, a metal coordination complex, a metal solvate, or a metal salt.

33. The method of claim 27, wherein the ligand is selected from a fatty acid, an amine, a phosphine, a phosphine oxide, a phosphonic acid or combination thereof.

34. The method of claim 33, wherein the fatty acid is selected from decanoic acid, oleic acid, lauric acid, myristic acid, palmitic acid, or stearic acid.

35. The method of claim 27, wherein the non-coordinating solvent has a melting point less than about 25°

C. and a boiling point greater than about 250°

C.

36. The method of claim 27, wherein the non-coordinating solvent is octadecene.

37. The method of claim 27, wherein the anion precursor is selected from an element, a covalent compound, or an ionic compound.

38. The method of claim 27, wherein the anion precursor is selected from elemental S, elemental Se, elemental Te, selenium tributylphosphine, or tellurium tributylphosphine.

39. The method of claim 27, wherein the anion precursor is combined with a non-coordinating solvent, a ligand, or a combination thereof prior to admixing with the cation-ligand complex.

40. The method of claim 27, wherein the temperature sufficient to form nanocrystals is greater than about 200°

C.

41. The method of claim 27, wherein nanocrystals of CdS are formed.

42. The method of claim 27, wherein nanocrystals of CdSe are formed.

43. The method of claim 27, wherein nanocrystals of CdTe are formed.

44. The method of claim 27, wherein nanocrystals of ZnSe are formed.

45. The method of claim 27, wherein nanocrystals of InP are formed.

46. The method of claim 27, wherein nanocrystals of InAs are formed.

47. The method of claim 27, wherein the mean diameter of the nanocrystals is from about 1 nm to about 6 nm.

48. A method of synthesizing colloidal nanocrystals, comprising:

a) combining a cation precursor, a ligand, and a non-coordinating solvent to form a cation-ligand complex;

b) admixing an anion precursor with the cation-ligand complex at a first temperature sufficient to induce reaction between the cation-ligand complex and the anion precursor; and

c) adjusting the temperature of the mixture to a second temperature sufficient to form nanocrystals of the reaction product.

49. The method of claim 48, wherein the anion precursor is combined with a non-coordinating solvent, a ligand, or a combination thereof prior to admixing with the cation-ligand complex.

50. The method of claim 48, wherein the cation precursor is CdO, the ligand is oleic acid, the non-coordinating solvent is octadecene, and the anion precursor is elemental sulfur.

51. The method of claim 48, wherein the cation precursor is CdO, the ligand is oleic acid, the non-coordinating solvent is octadecene, and the anion precursor is selenium tributylphosphine.

52. The method of claim 48, wherein the cation precursor is CdO, the ligand is oleic acid, the non-coordinating solvent is octadecene, and the anion precursor is tellurium tributylphosphine.

53. The method of claim 48, wherein the cation precursor is Zn(acetate)₂, the ligand is oleic acid, the non-coordinating solvent is octadecene, and the anion precursor is elemental selenium tributylphosphine.

54. The method of claim 48, wherein the cation precursor is In(acetate)₃, the ligand is selected from myristic acid or palmitic acid, the non-coordinating solvent is octadecene, and the anion precursor is P(SiMe₃)₃.

55. The method of claim 48, wherein the cation precursor is In(acetate)₃, the ligand is selected from myristic acid or palmitic acid, the non-coordinating solvent is octadecene, and the anion precursor is As(SiMe₃)₃.

56. (canceled)