Preparation of nanocrystallites

• US 6,576,291 B2
• Filed: 12/08/2000
• Issued: 06/10/2003
• Est. Priority Date: 12/08/2000
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Bawendi, Moungi, Stott, Nathan E.
• Primary Examiner(s): Le, H. Thi
• Application Number:
  US09/732,013
• Publication Number:
  US 20020071952A1
• Time in Patent Office: 914 Days
• Field of Search: 516/33, 516/922, 753/43, 753/70, 75/106.2, 753/62, 427/215, 427/314
• US Class Current: 427/215
• 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 19/007 Tellurides or selenides of metals C01B19/002 takes precedence
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• 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 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 7/14 the crystallising materials being formed by chemical reactions in the solution
• CPC Class Codes: H01L 33/005 Processes
• CPC Class Codes: H01L 33/0083 for devices with an active region comprising only II-VI compounds
• CPC Class Codes: Y10S 516/922 Colloid systems having specified particle size, range, or distribution, e.g. bimodal particle distribution
• CPC Class Codes: Y10S 977/813 Of specified inorganic semiconductor composition, e.g. periodic table group IV-VI compositions
• CPC Class Codes: Y10S 977/815 Group III-V based compounds, e.g. AlaGabIncNxPyAsz
• CPC Class Codes: Y10S 977/818 III-P based compounds, e.g. AlxGayIn2P
• CPC Class Codes: Y10S 977/819 III-As based compounds, e.g. AlxGayInzAs
• CPC Class Codes: Y10S 977/82 III-Sb based compounds, e.g. AlxGayInzSb
• CPC Class Codes: Y10S 977/822 Boron-containing compounds
• CPC Class Codes: Y10S 977/823 Tl-containing or Bi-containing compounds
• CPC Class Codes: Y10S 977/824 Group II-VI nonoxide compounds, e.g. CdxMnyTe
• CPC Class Codes: Y10S 977/916 : Gene therapy
• CPC Class Codes: Y10T 428/2991 : Coated

Abstract

A method of manufacturing a nanocrystallite from a M-containing salt forms a nanocrystallite. The nanocrystallite can be a member of a population of nanocrystallites having a narrow size distribution and can include one or more semiconductor materials. Semiconducting nanocrystallites can photoluminesce and can have high emission quantum efficiencies.

Claims

1. A method of manufacturing a nanocrystallite, comprising:

contacting a metal, M, or an M-containing salt, and a reducing agent to form an M-containing precursor, M being Cd, Zn, Mg, Hg, Al, Ga, In, or Tl;

contacting the M-containing precursor with an X donor, X being O, S, Se, Te, N, P, As, or Sb to form a mixture; and

heating the mixture in the presence of an amine to form the nanocrystallite.

2. The method of claim 1, wherein the amine is a primary amine.

3. The method of claim 2, wherein the primary amine is a C₈-C₂₀ alkyl amine.

4. The method of claim 1, wherein the reducing agent includes a 1,2-diol or an aldehyde.

5. The method of claim 4, wherein the 1,2-diol is a C₆-C₂₀ alkyl diol or the aldehyde is a C₆-C₂₀ aldehyde.

6. The method of claim 4, wherein the primary amine is a C₈-C₂₀ alkyl amine, the 1,2-diol is a C₆-C₂₀ alkyl diol, and the M-containing salt is a halide, carboxylate, carbonate, hydroxide, or diketonate.

7. The method of claim 1, wherein the M-containing salt includes a halide, carboxylate, carbonate, hydroxide, or diketonate.

8. The method of claim 1, wherein the M-containing salt includes cadmium acetylacetonate, cadmium iodide, cadmium bromide, cadmium hydroxide, cadmium carbonate, cadmium acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc hydroxide, zinc carbonate, zinc acetate, magnesium acetylacetonate, magnesium iodide, magnesium bromide, magnesium hydroxide, magnesium carbonate, magnesium acetate, mercury acetylacetonate, mercury iodide, mercury bromide, mercury hydroxide, mercury carbonate, mercury acetate, aluminum acetylacetonate, aluminum iodide, aluminum bromide, aluminum hydroxide, aluminum carbonate, aluminum acetate, gallium acetylacetonate, gallium iodide, gallium bromide, gallium hydroxide, gallium carbonate, gallium acetate, indium acetylacetonate, indium iodide, indium bromide, indium hydroxide, indium carbonate, indium acetate, thallium acetylacetonate, thallium iodide, thallium bromide, thallium hydroxide, thallium carbonate, or thallium acetate.

9. The method of claim 1, wherein the X donor includes a phosphine chalcogenide, a bis(silyl) chalcogenide, dioxygen, an ammonium salt, or a tris(silyl) pnictide.

10. The method of claim 1, wherein the nanocrystallite photoluminesces with a quantum efficiency of at least 10%.

11. The method of claim 1, further comprising monitoring the size distribution of a population including of the nanocrystallite.

12. The method of claim 11, further comprising lowering the temperature of the mixture in response to a spreading of the size distribution.

13. The method of claim 11, further comprising increasing the temperature of the mixture in response to when monitoring indicates growth appears to stop.

14. The method of claim 1, wherein the nanocrystallite has a particle size in the range of about 20 Å

to about 125 Å

.

15. The method of claim 1, wherein the heating takes place in the presence of a coordinating solvent.

16. The method of claim 15, wherein the semiconductor material is ZnS, ZnSe, CdS, CdSe, or mixtures thereof.

17. The method of claim 1, further comprising exposing the nanocrystallite to an organic compound having affinity for a surface of the nanocrystallite.

18. The method of claim 1, further comprising forming an overcoating of a semiconductor material on a surface of the nanocrystallite.

19. The method of claim 1, wherein the nanocrystallite is a member of a substantially monodisperse core population.

20. The method of claim 19, wherein the population emits light in a spectral range of no greater than about 75 nm full width at half max (FWHM).

21. The method of claim 19, wherein the population exhibits less than a 15% rms deviation in diameter of the nanocrystallite.

22. The method of claim 1, further comprising contacting elemental X with a phosphine to form the X donor.

23. A method of manufacturing a nanocrystallite, comprising:

contacting a metal, M, or an M-containing salt, and a reducing agent to form an M-containing precursor, M being Cd, Zn, Mg, Hg, Al, Ga, In, or Tl;

contacting the M-containing precursor with an X donor, X being O, S, Se, Te, N, P, As, or Sb to form a mixture; and

heating the mixture to form the nanocrystallite.

24. The method of claim 23, wherein the reducing agent includes a 1,2-diol or an aldehyde and the M-containing salt includes a halide, carboxylate, carbonate, hydroxide, or diketonate.

25. The method of claim 23, further comprising contacting elemental X with a phosphine to form the X donor.

26. A method of manufacturing a nanocrystallite, comprising:

contacting a metal, M, or an M-containing salt, M being Cd, Zn, Mg, Hg, Al, Ga, In, or Tl, a reducing agent, an amine, and an X donor, X being O, S, Se, Te, N, P, As, or Sb to form a mixture; and

heating the mixture to form the nanocrystallite.

27. The method of claim 26, wherein the amine is a C₆-C₂₀ primary amine and the M-containing salt includes a halide, carboxylate, carbonate, hydroxide, or diketonate.

28. A method of overcoating a core nanocrystallite comprising:

contacting a core nanocrystallite population with an M-containing salt, M being Cd, Zn, Mg, Hg, Al, Ga, In, or Tl, an X donor, X being O, S, Se, Te, N, P, As, or Sb, and an amine to form a mixture, and

forming an overcoating having the formula MX on a surface of the core.