Process for preparing a nanocrystalline material

• US 6,379,635 B2
• Filed: 09/09/1998
• Issued: 04/30/2002
• Est. Priority Date: 09/15/1995
• Status: Expired due to Term

• Current Assignee: Nanoco Technologies Limited (Nanoco Group Plc)
• Original Assignee: Imperial College of Science Technology & Medicine (Imperial College London)
• Inventors: OʼBrien, Paul, Dade, Tito Trin
• Primary Examiner(s): Griffin, Steven P.
• Assistant Examiner(s): JOHNSON, CHRISTINA ANN
• Application Number:
  US09/043,258
• Publication Number:
  US 20010005495A1
• Time in Patent Office: 1,329 Days
• Field of Search: 423/87, 423/92, 423/101, 423/122, 423/509, 423/566.1, 438/97, 136/258.AM, 362/800
• US Class Current: 423/87
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• 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: C01B 25/08 Other phosphides
• CPC Class Codes: C01B 32/15 Nano-sized carbon materials
• CPC Class Codes: C01G 11/02 Sulfides
• CPC Class Codes: C01G 15/00 Compounds of gallium, indium or thallium
• CPC Class Codes: C01G 9/08 Sulfides
• CPC Class Codes: C01P 2002/70 defined by measured X-ray, neutron or electron diffraction data
• CPC Class Codes: C01P 2002/80 defined by measured data other than those specified in group C01P2002/70
• CPC Class Codes: C01P 2002/84 by UV- or VIS- data
• CPC Class Codes: C01P 2002/85 by XPS, EDX or EDAX data
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/22 with a polygonal circumferential shape
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/34 Melting temperatures
• CPC Class Codes: C01P 2006/60 Optical properties, e.g. expressed in CIELAB-values
• CPC Class Codes: H01L 31/032 including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
• CPC Class Codes: H01L 31/1828 the active layers comprising only AIIBVI compounds, e.g. CdS, ZnS, CdTe
• CPC Class Codes: H01L 33/18 : within the light emitting region
• CPC Class Codes: H01L 33/20 : with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: Y02E 10/543 : Solar cells from Group II-VI materials

Abstract

A process for preparing a nanocrystalline material comprising at least a first ion and at least a second ion different from the first ion, and wherein at least the first ion is a metal ion, is described. The process comprises contacting a metal complex comprising the first ion and the second ion with a dispersing medium suitable to form the nanocrystalline material and wherein the dispersing medium is at a temperature to allow formation by pyrolysis of the nanocrystalline material when contacted with the metal complex.

Claims

1. A process for preparing a nanocrystalline material comprising at least a first ion and at least a second ion different from the first ion, the process comprising:

a single-step pyrolysis of a metal complex of the formula ML_n in a dispersing medium suitable to form the nanocrystalline material, wherein;

M represents a metal ion selected from the group consisting of a cadmium ion, a zinc ion, a lead ion, a mercury ion, an aluminum ion, an indium ion, a gallium ion and combinations thereof;

L represents one or more ligands selected from the group consisting of a sulphide group, a phosphide group, a thiol-carbamate group, a dithiol-carbamate group, a seleno-carbamate group, a diseleno-carbamate group, an organic group, a thio group and combinations thereof; and

n represents the valency of M;

further wherein the dispersing medium is at a temperature to allow formation of the nanocrystalline material by pyrolysis when the contacted with the metal complex.

2. The process according to claim 1 wherein the organic group is a di-C_1-6 alkyl group and/or thio group is a dithio group.

3. The process according to claim 1 wherein the organic group is an alkyl group which may be substituted and/or unsaturated.

4. The process according to claim 1 wherein the organic group is a dialkyl group, which may be substituted and/or unsaturated, and/or wherein the thio group is a dithio group.

5. The process according to claim 1 wherein the dispersing medium is at a temperature of 250°

C. or more.

6. The process according to claim 5, wherein the dispersing medium is at a temperature of about 300°

C. to 350°

C.

7. The process according to claim 1 wherein the dispersing medium passivates the surface of the nanocrystalline material.

8. The process according to claim 1 wherein the nanocrystalline material is selected from the group consisting of cadmium selenide, cadmium sulphide, zinc selenide, zinc sulphide, indium phosphate, gallium arsenide, and ternary and quaternary combinations thereof.

9. The process of claim 8, wherein the nanocrystalline material is cadmium selenide.

10. The process of claim 1 wherein the group includes an oxide ion, a selenide ion, or an arsenide ion.

11. The process of claim 10 wherein the group includes an oxide ion.

12. The process of claim 10 wherein the group includes a selenide ion.

13. The process of claim 10 wherein the group includes an arsenide ion.

14. The process of claim 1 wherein the metal complex is ((CH₃)CdSe₂CN(C₂H₅)₂)₂, (CH₃)₂InS₂CN(C₂H₅)₂, (CH₃)₂GaS₂CN(C₂H₅)₂, (C₂H₅)₂InS₂CN(C₂H₅)₂, (C₂H₅)₂GaS₂CN(C₂H₅)₂, (Np₂)₂InS₂CN(C₂H₅)₂, (Np₂)₂GaS₂CN(C₂H₅)₂, (Zn(S₂CNMeⁱPr)₂)₂, (Cd(S₂CNMeⁱPr)₂)₂, (Zn(As₂CNMeⁱPr)₂)₂, (Cd(As₂CNMeⁱPr)₂)₂, (C₅H₁₁)₂GaP^tBu₂, (C₅H₁₁)₂IndiumP^tBu₂, (C₅H₁₁)₂IndiumAs^tBu₂, or (C₅H₁₁)₂GalliumAs^tBu₂.

15. The process of claim 14 wherein the metal complex is ((CH₃)CdSe₂CN(C₂H₅)₂)₂, (CH₃)₂InS₂CN(C₂H₅)₂, (CH₃)₂GaS₂CN(C₂H₅)₂, ((C₂H₅)₂InS₂CN(C₂H₅)₂, (C₂H₅)₂GaS₂CN(C₂H₅)₂, (Np₂)₂InS₂CN(C₂H₅)₂, (Np₂)₂GaS₂CN(C₂H₅)₂, (Zn(S₂CNMeⁱPr)₂)₂, (Cd(S₂CNMeⁱPr)₂)₂, (Zn(As₂CNMeⁱPr)₂)₂, (Cd(As₂CNMeⁱPr)₂)₂, (C₅H₁₁)₂GaP^tBu₂.

16. The process of claim 1 wherein the metal complex is methyl diethyldiselenocarbamato cadmium II.

17. The process of claim 1 wherein the metal complex is diethyl diselenocarbamato cadmium or dithio diselenocarbamato cadmium.

18. The process of claim 1 wherein the metal complex contains at least one organic group and has a Formula II or III

19. The process of claim 18 wherein x is 2, y is 1, and z is 1 or 2.

20. The process of claim 19 wherein z is 2.

21. The process of claim 1 wherein the metal complex contains at least one organic group and has a Formula V or VI

22. The process of claim 1 wherein the metal complex is a thiolate, a thiophosphinate, or a phosphinochalogen.