Passivated nanoparticles, method of fabrication thereof, and devices incorporating nanoparticles

• US 7,253,119 B2
• Filed: 05/09/2005
• Issued: 08/07/2007
• Est. Priority Date: 09/05/2001
• Status: Expired due to Term

• Current Assignee: Rensselaer Polytechnic Institute
• Original Assignee: Rensselaer Polytechnic Institute
• Inventors: Dutta, Partha
• Primary Examiner(s): Estrada; Michelle
• Assistant Examiner(s): STARK, JARRETT J
• Application Number:
  US11/124,244
• Publication Number:
  US 20050201963A1
• Time in Patent Office: 820 Days
• Field of Search: 977/778, 977/856, 977/847, 977/888, 257/E21.214
• US Class Current: 438/754
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 19/007 Tellurides or selenides of metals C01B19/002 takes precedence
• CPC Class Codes: C01G 21/21 Sulfides
• CPC Class Codes: C01P 2004/52 highly monodisperse size distribution
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: C09D 11/52 Electrically conductive inks
• CPC Class Codes: C09D 5/028 Pigments; Filters
• CPC Class Codes: C09D 5/24 Electrically-conducting paints conductive materials H01B1/00
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• 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 21/02521 Materials
• CPC Class Codes: H01L 21/02568 Chalcogenide semiconducting materials not being oxides, e.g. ternary compounds
• CPC Class Codes: H01L 21/02601 Nanoparticles fullerenes H10K85/211
• CPC Class Codes: H01L 21/02628 using solutions
• CPC Class Codes: H01L 21/02664 Aftertreatments planarisation in general H01L21/304
• CPC Class Codes: H10K 50/11 : characterised by the electroluminescent [EL] layers
• CPC Class Codes: Y10S 977/778 : within specified host or matrix material, e.g. nanocomposite films
• CPC Class Codes: Y10S 977/786 : Fluidic host/matrix containing nanomaterials
• CPC Class Codes: Y10S 977/813 : Of specified inorganic semiconductor composition, e.g. periodic table group IV-VI compositions
• CPC Class Codes: Y10S 977/835 : Chemical or nuclear reactivity/stability of composition or compound forming nanomaterial
• CPC Class Codes: Y10S 977/847 : Surface modifications, e.g. functionalization, coating
• CPC Class Codes: Y10S 977/856 : including etching/cutting
• CPC Class Codes: Y10S 977/888 : Shaping or removal of materials, e.g. etching
• CPC Class Codes: Y10T 428/2991 : Coated

Abstract

A plurality of semiconductor nanoparticles having an elementally passivated surface are provided. These nanoparticles are capable of being suspended in water without substantial agglomeration and substantial precipitation on container surfaces for at least 30 days. The method of making the semiconductor nanoparticles includes reacting at least a first reactant and a second reactant in a solution to form the semiconductor nanoparticles in the solution. A first reactant provides a passivating element which binds to dangling bonds on a surface of the nanoparticles to passivate the surface of the nanoparticles. The nanoparticle size can be tuned by etching the nanoparticles located in the solution to a desired size.

Claims

1. A method of making semiconductor nanoparticles, comprising:

forming semiconductor nanoparticles of a first size in an aqueous solution; and

providing an etching liquid into the solution to etch the semiconductor nanoparticles of the first size to a second size smaller than the first size;

wherein the solution contains a passivating element which binds to dangling bonds on a surface of the nanoparticles to passivate the surface of the nanoparticles.

2. The method of claim 1, wherein:

the etching liquid comprises hydrochloric acid.

3. The method of claim 2, wherein the step of forming semiconductor nanoparticles comprises combining a metal Group IIB or lead compound and a Group VI compound in a solvent comprising water.

4. The method of claim 3, wherein:

the metal compound comprises a Pb, Zn or Cd compound; and

the Group VI compound comprises a sulfur compound.

5. The method of claim 4, wherein:

Pb, Zn or Cd compound comprises PbO, ZnO or CdO; and

the sulfur compound comprises ammonium sulfide.

6. The method of claim 4, wherein:

Pb, Zn or Cd compound comprises PbCl₂, ZnCl₂ or CdCl₂; and

the sulfur compound comprises sodium sulfide.

7. The method of claim 4, wherein the solution comprises an excess amount of sulfur which binds to dangling bonds on a surface of the nanoparticles to passivate the surface of the nanoparticles.

8. The method of claim 7, wherein the sulfur compound comprises (NH₄)₂S_1+x which provides the excess amount of sulfur which binds to the dangling bond.

9. The method of claim 7, wherein the solution contains a larger molar amount of sulfur compound than the molar amount of the Pb, Zn or Cd compound to provide the excess amount of sulfur which binds to dangling bonds.

10. A method of making semiconductor nanoparticles, comprising reacting at least a first reactant and a second reactant in a solution to form the semiconductor nanoparticles in the solution, wherein the first reactant provides a passivating element which binds to dangling bonds on a surface of the nanoparticles to passivate the surface of the nanoparticles.

11. The method of claim 10, wherein the semiconductor nanoparticles comprise II-VI, III-V or IV-VI semiconductor nanoparticles.

12. The method of claim 11, wherein:

the first reactant comprises (NH₄)₂S_1+x;

the second reactant comprises a lead, cadmium or zinc compound; and

the nanoparticles comprise PbS, CdS or ZnS nanoparticles having a sulfur passivated surface.

13. The method of claim 11, wherein:

the first reactant comprises liquid (NH₄)₂SeO₄,

the second reactant comprises solid a lead, cadmium or zinc compound; and

the nanoparticles comprise PbSe, CdSe or ZnSe nanoparticles having a selenide passivated surface.

14. The method of claim 11, further comprising providing a third reactant comprising a Group V element compound;

wherein;

the first reactant comprises liquid (NH₄)₂S_1+x;

the second reactant comprises a Group III element compound; and

the nanoparticles comprise III-V semiconductor nanoparticles having a surface passivated by at least one of sulfur and hydrogen.

15. The method of claim 10, further comprising diluting at least one reactant with water.

16. The method of claim 10, further comprising adding an acid to the solution.

17. The method of claim 16, wherein the acid comprises HCl.

18. The method of claim 10, wherein:

the passivating element comprises sulfur;

the first and the second reactants comprise inorganic reactants; and

the reaction is carried out in an aqueous solution.

19. The method of claim 18, wherein the nanoparticles remain suspended in the solution for at least 30 days without substantial agglomeration and without substantial precipitation from the solution.

20. The method of claim 10, further comprising:

removing the nanoparticles from the solution; and

placing the nanoparticles into an article.

21. A method of making semiconductor nanoparticles, comprising etching semiconductor nanoparticles of a first size to a second size smaller than the first size, wherein:

the step of etching comprises providing an etching liquid into an aqueous solution containing the semiconductor nanoparticles of the first size; and

the solution contains a passivating element which binds to dangling bonds on a surface of the nanoparticles to passivate the surface of the nanoparticles.

22. The method of claim 21, wherein the semiconductor nanoparticles of the first size comprise crystalline semiconductor nanoparticles.

23. The method of claim 22, wherein the semiconductor nanoparticles of the first size comprise metal sulfide, selenide or telluride semiconductor nanoparticles.

24. The method of claim 23, wherein:

the etching liquid comprises hydrochloric acid.

25. The method of claim 23, wherein the nanoparticles remain suspended in the solution for at least 30 days without substantial agglomeration and without substantial precipitation from the solution.

26. The method of claim 21, wherein the semiconductor nanoparticles comprise II-VI, III-V or IV-VI semiconductor nanoparticles.

27. The method of claim 21, wherein the semiconductor nanoparticles of the first size have a random size distribution and the semiconductor nanoparticles of the second size have a uniform size distribution.

28. The method of claim 21, wherein the semiconductor nanoparticles of the second size have an average size between 2 and 100 nm.

29. The method of claim 28, further comprising reacting at least a first sulfur containing reactant and a second reactant in an aqueous solution to form the semiconductor nanoparticles of the first size in the solution, wherein the first reactant provides a sulfur passivating element which binds to dangling bonds on a surface of the nanoparticles to passivate the surface of the nanoparticles.

30. The method of claim 21, further comprising placing the nanoparticles into an article.