Controlled preparation of nanoparticle materials

• US 20070104865A1
• Filed: 10/27/2006
• Published: 05/10/2007
• Est. Priority Date: 10/28/2005
• Status: Active Grant

• Current Assignee: Nanoco Technologies Limited (Nanoco Group Plc)
• Original Assignee: Nanoco Technologies Limited (Nanoco Group Plc)
• Inventors: Pickett, Nigel
• Granted Patent: US 7,867,556 B2
• Time in Patent Office: Days
• US Class Current: 427/212
• 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: C01B 17/20 Methods for preparing sulfides or polysulfides, in general ammonium sulfides or polysulfides C01C; sulfides or polysulfides of metals, other than alkali metals, magnesium, calcium, strontium and barium, see the relevant groups of subclasses C01F or C01G, according to the metal
• CPC Class Codes: C01B 19/002 Compounds containing, besides selenium or tellurium, more than one other element, with -O- and -OH not being considered as anions
• CPC Class Codes: C01B 19/007 Tellurides or selenides of metals C01B19/002 takes precedence
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/84 by UV- or VIS- data
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2004/80 Particles consisting of a mixture of two or more inorganic phases
• CPC Class Codes: C01P 2004/84 one phase coated with the other
• 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: C30B 7/005 Epitaxial layer growth
• CPC Class Codes: H01L 29/127 Quantum box structures
• 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.]
• CPC Class Codes: Y10T 428/2995 Silane, siloxane or silicone coating
• CPC Class Codes: Y10T 428/2996 Glass particles or spheres

Abstract

A method of producing nanoparticles comprising effecting conversion of a nanoparticle precursor composition to the material of the nanoparticles, the precursor composition comprising a first precursor species containing a first ion to be incorporated into the growing nanoparticles and a second precursor species containing a second ion to be incorporated into the growing nanoparticles, said conversion being effected in the presence of a molecular cluster compound under conditions permitting seeding and growth of the nanoparticles.

Claims

1. A method of producing nanoparticles comprising:

effecting conversion of a nanoparticle precursor composition to a material of the nanoparticles, the precursor composition comprising a first precursor species containing a first ion to be incorporated into the nanoparticles and a second precursor species containing a second ion to be incorporated into the nanoparticles, the conversion being effected in the presence of a molecular cluster compound under conditions permitting seeding and growth of the nanoparticles, by

dispersing the molecular cluster compound and an initial portion of the nanoparticle precursor composition which is less than the total amount of the nanoparticle precursor composition to be used to produce the nanoparticles in a suitable dispersing medium at a first temperature;

increasing a temperature of the dispersing medium containing the cluster compound and precursor composition to a second temperature sufficient to initiate seeding and growth of the nanoparticles on the molecular clusters of the molecular cluster compound; and

adding at least one further portion of the nanoparticle precursor composition to the dispersing medium containing the nanoparticles,

wherein the temperature of the dispersing medium containing the nanoparticles is increased at least before, during, or after the addition of the at least one further portion of the nanoparticle precursor composition.

2. A method in accordance with claim 1, wherein the temperature of the dispersing medium containing the nanoparticles is increased at a rate selected from a range of 0.05°

C./min to 1°

C./min, or at a rate of approximately 0.2°

C./min.

3. A method in accordance with claim 1, wherein a ratio of the number of moles of cluster compound compared to the total number of moles of the first and second precursor species is selected from a range 0.0001-0.1:

1, or from a range of 0.001-0.1;

1.

4. A method in accordance with claim 1, wherein a molar ratio of the first precursor species to the second precursor species is selected from a range of 100-1:

1, or 50-1;

1.

5. A method in accordance with claim 1, wherein said first temperature is selected from a range of 15°

C. to 60°

C.

6. A method in accordance with claim 1, wherein said second temperature is selected from a range 90°

C. to 150°

C.

7. A method in accordance with claim 1, wherein the at least one further portion of the nanoparticle precursor composition is added dropwise to the dispersing medium containing the nanoparticles.

8. A method in accordance with claim 1, wherein the at least one further portion of the nanoparticle precursor composition is added to the dispersing medium containing the nanoparticles at a rate selected from a range of 0.1 ml/min to 20 ml/min per litre of dispersing medium.

9. A method in accordance with claim 1, wherein said initial portion of the nanoparticle precursor composition is less than or equal to approximately 90% of the total amount of the nanoparticle precursor composition to be used to produce said nanoparticles.

10. A method in accordance with claim 1, wherein said initial portion of the nanoparticle precursor composition is less than or equal to approximately 10% of the total amount of the nanoparticle precursor composition to be used to produce said nanoparticles.

11. A method in accordance with claim 1, wherein a second portion of the nanoparticle precursor composition is added to the dispersing medium containing the nanoparticles and said second portion is less than or equal to approximately 90% of the total amount of the nanoparticle precursor composition to be used to produce said nanoparticles.

12. A method in accordance with claim 1, wherein more than one portion of the nanoparticle precursor composition is added to the dispersing medium containing the nanoparticles and each further portion of the nanoparticle precursor composition is less than or equal to approximately 45% of the total amount of the nanoparticle precursor composition to be used to produce said nanoparticles.

13. A method in accordance with claim 1, wherein more than one portion of the nanoparticle precursor composition is added to the dispersing medium containing the nanoparticles and each further portion is less than or equal to approximately 10% of the total amount of the nanoparticle precursor composition to be used to produce said nanoparticles.

14. A method in accordance with claim 1, wherein formation of said molecular cluster compound is effected in situ in said dispersing medium prior to dispersing the molecular cluster compound and the initial portion of the nanoparticle precursor composition in said dispersing medium.

15. A method in accordance with claim 1, wherein said dispersing medium is a Lewis base coordination compound selected from the group consisting of a phosphine, a phosphine oxide and an amine.

16. A method in accordance with claim 1, wherein the method comprises monitoring the average size of the nanoparticles being grown;

and terminating nanoparticle growth when the average nanoparticle size reaches a predetermined value.

17. A method in accordance with claim 16, wherein nanoparticle growth is terminated by reducing the temperature of the solution from the second temperature to a third temperature.

18. A method in accordance with claim 1, wherein the molecular cluster compound comprises third and fourth ions to be incorporated into the nanoparticles.

19. A method in accordance with claim 18, wherein the third ion is selected from group 12 of the periodic table and the fourth ion is selected from group 16 of the periodic table.

20. A method in accordance with claim 19, wherein the molecular cluster compound comprises molecules selected from the group consisting of [{(PPh₃)Hg}₄(SPh)₆], (Ph₄P)₂[(SEt)₅(Br)(HgBr)₄], (Ph₄P)₂[Hg₄(SEt)₅Br], [Hg₄Tel₂][N(CH₂CH₂Et)₄]₄, [Et₃NH]₄[Cd₁₀Se₄(SPh)₁₆], [RME^tBu]₅ where M=Zn, Cd or Hg, E=S, Se or Te, and R=Me or Et, [X]₄[E₄M₁₀(SR)₁₆] where M=Zn, Cd or Hg, E=S, Se or Te, X=Me₃NH⁺, Li⁺ or Et₃NH⁺, and R=Me, Et or Ph, [Cd₃₂S₁₄(SPh)₃₆]·

L where L=is a coordinating ligand, [Hg₁₀Se₄(SePh)(PPh₂ⁿPr)₄], [Hg₃₂Sel₄(SePh)₃₆], [Cd₁₀Se₄(SePh)₁₂(PPr₃)₄], [Cd₃₂Sel₄(SePh)₃₆(PPh₃)₄], [M₄(SPh)₁₂]+[X]₂⁻

where M=Zn, Cd or Hg, and X =Me₄N⁺, Li⁺, [Zn(SEt)Et]₁₀, [MeMEⁱPr] where M=Zn, Cd or Hg, and E=S, Se or Te, [RCdSR′

]₅ where R=O(C₁₀₃), R′

=PPh₃ or ⁱPr, [Cd₁₀E₄(E′

Ph)₁₂(PR₃)₄] where E=Te, Se or S, E′

=Te, Se or S, and R=is a coordinating ligand, [Cd₈Se(SePh)₁₂Cl₄]²⁻

, [M₄Te₁₂]⁴⁴⁻

where M=Cd or Hg, and [Ph₁₂M₁₈Cd₁₀(PEt₃)₃] where M=Te or Se.

21. A method in accordance with claim 18, wherein the third ion is selected from group 12 of the periodic table and the fourth ion is selected from group 15 of the periodic table.

22. A method in accordance with claim 21, wherein the molecular cluster compound comprises molecules selected from the group consisting of [RCdNR′

]₄ where R=Cl, Br, I, PEt₃ or C=CSMe₃, and R′

=PEt₃ or I, [RCdNR′

]₅ where R=alkyl or aryl group, and R′

=alkyl or aryl group, [{RZn}₆{PR′

}₄] where R=I or PEt₂Ph, and R′

=SiMe₃, [M₄Cl₄(PPh₂)₄(PnPr₃)₂] where M=Zn or Cd, [Li(thf)₄]₂[(Ph₂P)₁₀Cd₄], [Zn4(PPh₂)₄Cl₄(PRR′

₂)₂] where PRR′

₂ =PMeⁿPr₂, PⁿBu₃ or PEt₂Ph, and [Zn4(P^tBu₂)₄Cl₄].

23. A method in accordance with claim 18, wherein the third ion is selected from group 13 of the periodic table and the fourth ion is selected from group 15 of the periodic table.

24. A method in accordance with claim 23, wherein the molecular cluster compound comprises molecules selected from the group consisting of [EtGaNEt]₆, [MeGaN(4-C₆H₄F)]₆, (MeGaNiBu)₆, [RA1NR′

]₄ where R=Me, CH₂Prⁱ or Ph, and R′

=Prⁱ, CH₂Prⁱ, C₆H₂Me₃, [(SiPrⁱ₃)₃AsAlH]₆, [ⁱPrNA1H]₄, [RAlNR′

]₆ where R=Me, Et, Cl, CH₂Ph, CH₂Prⁱ or Ph, and R′

=Me, H, Br, C=CPh, Prⁱ, (CH₂)₂Me, (CH₂)2NMe₂ or SiPh₃, [CH₃Ga═

NCH₂CH(CH₃)₂]₆, [MeGaNⁱBu]₆, [RGaNR′

]₄ where R=Ph or Me, and R′

=Ph, C₆F₅, SiMe₃ or ^tBu, [EtGaNEt]₆, [RGaPR′

]₄ where R=ⁱPr or C₆H₂Me₃, and R′

=^tBu or C₆H₂Me₃, [RNInR′

]₄ where R=Cl, Br, I or Me, and R′

=^tBu, C₆F₅ or C₆H₄F, [RInPR′

]₄ where R=ⁱPr, C₆H₂Me₃ or Et, and R′

=SiPh₃, C₆H₂Me₃, Si′

Pr₃, and [RInPR′

]₆ where R=Et, and R′

=SiMe₂(CMe₂ⁱPr).

25. A method in accordance with claim 18, wherein the third ion is selected from group 13 of the periodic table and the fourth ion is selected from group 16 of the periodic table.

26. A method in accordance with claim 25, wherein the molecular cluster compound comprises molecules selected from the group consisting of [(^tBu)GaSe]₄, [^tBuGaS]₇, [RInSe]₄ where R=^tBu, CMe₂Et, Si(^tBu)₃ or C((SiMe₃)₃)₃, [RInS]₄ where R=^tBu or CMe₂Et, [RGaS]₄ where R=^tBu, CMe₂Et or CEt₃, [SAlR]₄ where R=C(SMe₃)₃ or CEtMe₂, [SAlNMe₃]₅, [TeAlR]₄ where R=Cp* or CEtMe₂, [(C(SiMe₃)₃)GaS]₄, [^tBuGaS]₆, [RGaSe]₄ where R=tBu, CMe₂Et, CEt₃, C(SiMe₃)₃, Cp* or Bu, Cd₄In₁₆S₃₃.(H₂O)₂₀(C₁₀H₂₈N₄)_2.5.

27. A method in accordance with claim 18, wherein the third ion is selected from group 14 of the periodic table and the fourth ion is selected from group 16 of the periodic table.

28. A method in accordance with claim 27, wherein the molecular cluster compound comprises molecules selected from the group consisting of [S₆{SnR}₄] where R=C(SiMe₃)₃, Me or Ph, [Se₆{SnR}₄] where R=C₆F₅, C₆H₂Me₃, p-Tol or C(SiMe₃)₃.

29. A method in accordance with claim 18, wherein the third ion is selected from the transition metal group of the periodic table and the fourth ion is selected the d-block of the periodic table.

30. A method in accordance with claim 29, wherein the molecular cluster compound comprises molecules selected from the group consisting of [Cu₁₂Se₆(PR)₈] where R=Et₂Ph, ⁿPr₃ or Cy₃, [Cu₁₈Te₆(^tBu)₆(PPh₂Et)₇], [Cu₁₉Te₆(^tBu)₇(PEt₃)₈], [Cu₂₇Te₁₅(PⁱPr₂Me)₁₂], [Ni₃₄Se₂₂(PPh₃)₁₀], [Ag₃₀(TePh)₁₂Te₉(PEt₃)₁₂], [Ag₃₀Se₈(Se^tBu)₁₄(PⁿPr₃)s], [Co4(μ

₃-Se)₄(PPh₃)₄], [Co₆(μ

₃-Se)₈(PPh₃)₆], [W₃Se₄(dmpe)₃Br₃]+, Ru₄Bi₂(CO)₁₂, Fe₄P₂(CO)₁₂, and Fe₄N₂(CO)₁₂.

31. A method in accordance with claim 1, wherein said first ion is selected from the group consisting of group 2 of the periodic table, group 12 of the periodic table, group 13 of the periodic table and group 14 of the periodic table.

32. A method in accordance with claim 1, wherein said second ion is selected from the group consisting of group 14 of the periodic table, group 15 of the periodic table and group 16 of the periodic table.

33. A method in accordance with claim 1, wherein the second precursor species is separate to the first precursor species in the nanoparticle precursor composition.

34. A method in accordance with claim 33, wherein said first precursor species is selected from the group consisting of an organometallic compound, an inorganic salt, and a coordination compound.

35. A method in accordance with claim 33, wherein the first precursor species is obtained by dissolving an elemental source selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Cd, Hg, B, Al, Ga, In, Sn, and Pb in a suitable solvent.

36. A method in accordance with claim 33, wherein the second precursor species is selected from the group consisting of an organo compound, a hydrido compound, an inorganic salt, and a coordination compound.

37. A method in accordance with claim 1, wherein the first and second precursor species are part of a single chemical entity in the nanoparticle precursor composition.

38. A method in accordance with claim 37, wherein said single chemical entity is selected from the group consisting of an organometallic compound, an inorganic salt and a coordination compound.

39. A method in accordance with claim 37, wherein said single chemical entity incorporates ions selected from the group consisting of group 12 and group 16 of the periodic table, or group 13 and group 15 of the periodic table, group 12 and group 15 of the periodic table, and group 14 and group 16 of the periodic table.

40. A method in accordance with claim 1, wherein the nanoparticles have cores comprising a core compound comprising fifth and sixth ions.

41. A method in accordance with claim 40, wherein the fifth ion is selected from group 2 of the periodic table and the sixth ion is selected from group 16 of the periodic table, or wherein the fifth ion is selected from group 12 of the periodic table and the sixth ion is selected from group 16 of the periodic table, or wherein the fifth ion is selected from group 12 of the periodic table and the sixth ion is selected from group 15 of the periodic table, or wherein the fifth ion is selected from group 13 of the periodic table and the sixth ion is selected from group 15 of the periodic table, or wherein the fifth ion is selected from group 13 of the periodic table and the sixth ion is selected from group 14 of the periodic table, or wherein the firth ion is selected from group 13 of the periodic table and the sixth ion is selected from group 16 of the periodic table, or wherein the fifth ion is selected from group 14 of the periodic table and the sixth ion is selected from group 16 of the periodic table, or wherein the fifth ion is selected from the transition metal group of the periodic table and the sixth ion is selected from the d-block of the periodic table.

42. A method in accordance with claim 40, wherein the nanoparticle cores comprise a dopant selected from the group consisting of a main group element, and a rare earth element.

43. A method in accordance with claim 40, wherein each nanoparticle comprises at least one shell grown onto the nanoparticle core.

44. A method in accordance with claim 43, wherein the at least one shell has a similar lattice type to the nanoparticle core.

45. A method in accordance with claim 43, wherein the at least one shell has a wider band-gap than the nanoparticle core.

46. A method in accordance with claim 43, wherein the at least one shell comprises a shell compound comprised of seventh and eighth ions.

47. A method in accordance with claim 46, wherein the seventh ion is selected from group 2 of the periodic table and the eighth ion is selected from group 16 of the periodic table, or wherein the seventh ion is selected from group 12 of the periodic table and the eighth ion is selected from group 16 of the periodic table, or wherein the seventh ion is selected from group 12 of the periodic table and the eighth ion is selected from group 15 of the periodic table, or wherein the seventh ion is selected from group 13 of the periodic table and the eighth ion is selected from group 15 of the periodic table, or wherein the seventh ion is selected from group 13 of the periodic table and the eighth ion is selected from group 14 of the periodic table, or wherein the seventh ion is selected from group 13 of the periodic table and the eighth ion is selected from group 16 of the periodic table, or wherein the seventh ion is selected from group 14 of the periodic table and the eighth ion is selected from group 16 of the periodic table, or wherein the seventh ion is selected from the transition metal group of the periodic table and the eighth ion is selected from the d-block of the periodic table.

48. A method of producing nanoparticles comprising:

effecting conversion of a nanoparticle precursor composition to a material of the nanoparticles, said precursor composition comprising a first precursor species containing a first ion to be incorporated into the nanoparticles and a separate second precursor species containing a second ion to be incorporated into the nanoparticles, said conversion being effected in the presence of a molecular cluster compound under conditions permitting seeding and growth of the nanoparticles, wherein the method comprises;

dispersing the molecular cluster compound and an initial portion of one of the first and second precursor species which is less than the total amount of said one of the first and second precursor species to be used to produce said nanoparticles in a suitable dispersing medium at a first temperature;

increasing the temperature of the dispersing medium containing the cluster compound and said one of the first and second precursor species to a second temperature which is sufficient to initiate seeding and growth of the nanoparticles on the molecular clusters of said molecular cluster compound; and

adding at least one further portion of said one of the first and second precursor species to the dispersing medium containing the nanoparticles,

wherein the temperature of the dispersing medium containing the nanoparticles is increased at least before, during, or after the addition of the at least one portion of said one of the first and second precursor species.

49. A method in accordance with claim 48, wherein the method further comprises adding to the dispersing medium, when the dispersing medium is at said second temperature, an initial portion of the other of the first and second precursor species which is less than the total amount of said other of said first and second precursor species to be used to produce said nanoparticles.

50. A method in accordance with claim 49, wherein at least one further portion of said other of said first and second precursor species is added to the dispersing medium containing the nanoparticles.

51. A method in accordance with claim 50, wherein the temperature of the dispersing medium containing the nanoparticles is increased at least before, during, or after the addition of the at least one further portion of said other of the first and second precursor species.

52. A method in accordance with claim 50, wherein a temperature of the dispersing medium containing the nanoparticles is maintained at approximately said second temperature during the addition of the at least one further portion of said other of the first and second precursor species.

53. A method in accordance with claim 48, wherein nanoparticle growth is terminated by reducing the temperature of the solution from the second temperature to a third temperature.

54. A method in accordance with claim 48, wherein the temperature of the dispersing medium containing the nanoparticles is increased from the first temperature to the second temperature at a rate selected from a range of 0.05°

C./min to 2°

C./min.

55. A method in accordance with claim 48, wherein the temperature of the dispersing medium containing the nanoparticles is increased from the first temperature to the second temperature at a rate selected from a range of 0.5°

C./min to 1.5°

C./min.

56. A method in accordance with claim 48, wherein said first temperature is selected from a range of 15°

C. to 80°

C.

57. A method in accordance with claim 48, wherein said second temperature is selected from a range of 140°

C. to 300°

C.

58. A method in accordance with claim 48, wherein the at least one further portion of one of the first and second precursor species is added dropwise to the dispersing medium containing the nanoparticles.