Preparation of nanocrystallites

• US 20050084443A1
• Filed: 10/08/2004
• Published: 04/21/2005
• Est. Priority Date: 12/08/2000
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Bawendi, Moungi, Stott, Nathan E.
• Granted Patent: US 7,138,098 B2
• Time in Patent Office: Days
• US Class Current: 423/561.100
• 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 nanocrystal comprising heating a mixture including a coordinating solvent, a chalcogen or pnictide source, and a metal-containing compound to form a nanocrystal, wherein the metal-containing compound is free of metal-carbon bonds.

2. The method of claim 1, wherein the mixture further comprises 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 mixture further comprises 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 1, wherein the metal-containing compound includes a halide, carboxylate, carbonate, hydroxide, or diketonate.

7. The method of claim 1, wherein the metal-containing compound includes a Group II metal or a Group III metal.

8. The method of claim 1, wherein the metal-containing compound 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 mixture further comprises a C₈-C₂₀ alkyl primary amine, a C₆-C₂₀ alkyl 1,2-diol, and the metal-containing compound is a halide, carboxylate, carbonate, hydroxide, or diketonate.

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

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

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

13. The method of claim 12, further altering the temperature of the mixture in response to a change in the size distribution.

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

to about 125 Å

.

15. The method of claim 1, wherein the nanocrystal includes ZnS, ZnSe, CdS, CdSe, or mixtures thereof.

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

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

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

19. The method of claim 18, wherein the population emits light in a spectral range of no greater than about 75 nm full width at half max (FWHM).

20. The method of claim 18, wherein the population exhibits less than a 15% rms deviation in diameter of the nanocrystal.

21. A method of manufacturing a nanocrystal, 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 nanocrystal.

22. The method of claim 21, 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.

23. A method of manufacturing a nanocrystal, comprising:

contacting a metal, M, or an M-containing salt, M being Cd, Zn, Mg, Hg, Al, Ga, In, or Tl, 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 nanocrystal.

24. The method of claim 23, wherein the amine is a C₆-C₂₀ primary amine and the M-containing salt includes a halide, carboxylate, carbonate, hydroxide, or diketonate.

25. A method of overcoating a core nanocrystal comprising:

contacting a core nanocrystal 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.