III-V semiconductor core-heteroshell nanocrystals

• US 20090230382A1
• Filed: 06/15/2006
• Published: 09/17/2009
• Est. Priority Date: 06/15/2005
• Status: Active Grant

• Current Assignee: Yissum Research Development Company of the Hebrew University of Jerusalem Ltd. (Hebrew University of Jerusalem)
• Original Assignee: Yissum Research Development Company of the Hebrew University of Jerusalem Ltd. (Hebrew University of Jerusalem)
• Inventors: Banin, Uri, Aharoni, Assaf
• Granted Patent: US 7,964,278 B2
• Time in Patent Office: Days
• US Class Current: 257/14
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/70 containing phosphorus
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: C30B 29/60 characterised by shape
• CPC Class Codes: C30B 7/005 Epitaxial layer growth
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01S 5/3412 quantum box or quantum dash
• CPC Class Codes: Y10T 428/2991 Coated

Abstract

The present invention provides a core/multishell semiconductor nanocrystal comprising a core and multiple shells, which exhibits a type-I band offset and high photoluminescence quantum yield providing bright tunable emission covering the visible range from about 400 nm to NIR over 1600 nm.

Claims

1. A core/multishell semiconductor nanocrystal comprising a core material made of a III/V compound and at least two shell materials, wherein a first shell material coats the core material, a second shell material coats the first shell material, and sequentially each subsequent shell material coats the preceding shell, each shell material being independently selected from a II/VI, III/V or III/VI compound, wherein the core material is different from the first shell material, and any shell material is different from the shell material of the adjacent shells, and wherein the said nanocrystal exhibits a type-I band offset and luminescence at a wavelength from about 400 to about 1600 nm.

2. The core/multishell semiconductor nanocrystal according to claim 1, wherein

(i) the band gap of the core material is less than the band gap of the first and subsequent shell materials;

(ii) the band gap of the first shell material is larger than the band gap of the core material and lower than the band gap of subsequent shell materials; and

(iii) the band gap of the second or subsequent shell material is larger than that of the first or preceding shell material and lower than the band gap of subsequent shell materials.

3. The core/multishell semiconductor nanocrystal according to claim 1, comprising a core material and between 2 and 7 shell materials.

4. The core/multishell semiconductor nanocrystal of claim 1 being an undoped nanocrystal.

7. The core/multishell semiconductor nanocrystal according to claim 1, wherein said core material made of a III/V compound is selected from InAs, InP, GaAs, GaP, GaSb, InSb, AlAs, AlP, AlSb, InGaAs, GaAsP, and InAsP.

8. The core/multishell semiconductor nanocrystal according to claim 7, wherein said core material is InAs, InP or GaAs.

9. The core/multishell semiconductor nanocrystal according to claim 1, wherein said at least two shell materials are selected from II/VI compounds.

10. The core/multishell semiconductor nanocrystal according to claim 1, wherein said at least two shell materials are selected from III/V compound.

11. The core/multishell semiconductor nanocrystal according to claim 1, wherein said at least two shell materials are selected from III/VI compound.

12. The core/multishell semiconductor nanocrystal according to claim 9, wherein said II/VI compound is selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdZnSe, CdSSe, and ZnSSe.

13. The core/multishell semiconductor nanocrystal according to claim 10, wherein said III/V compound is selected from InAs, GaAs, GaP, GaSb, InP, InSb, AlAs, AlP, AlSb, InGaAs, GaAsP, and InAsP.

14. The core/multishell semiconductor nanocrystal according to claim 11, wherein said III/VI compound is selected from InS, In₂S₃, InSe, In₂Se₃, In₄Se₃, In₂Se₃, InTe, In₂Se₃, GaS, Ga₂Se₃, GaSe, Ga₂Se₃, GaTe, Ga₂Te₃, In₂Se_3-xTe_x, GaTeSe, and (Ga_xIn_1-x)Se₃, wherein X is zero or 1.

15. The core/multishell semiconductor nanocrystal according to claim 1 being selected from InAs/CdSe/ZnS, InAs/CdSe/CdS, InAs/InP/ZnSe, InP/ZnSe/ZnS, InP/CdS/ZnSe, InP/CdS/ZnSe, GaAs/CdSe/ZnS, and GaAs/CdS/ZnS.

16. The core/multishell semiconductor nanocrystal according to claim 1 being InAs/CdSe/ZnSe or InP/ZnSe/ZnS.

24. A wideband optical amplifier for amplifying data-carrying optical signals, comprising a plurality of the core/multishell semiconductor nanocrystals according to any one of claims 1 to 16, wherein each of said core/multishell nanocrystals has core dimensions that correspond to a specific optical band and is located at a predetermined point within a light transmitting medium;

and a pumping, coherent-light source connected to said light transmitting medium for exciting each of said nanocrystals with light energy required for the amplification of data-carrying optical signals within said specific optical band, received in said light transmitting medium.

25. A light-emitting diode comprising a plurality of the core/multishell semiconductor nanocrystals according to claim 1.

26. A biological labeling agent comprising a plurality of the core/multishell semiconductor nanocrystals according to claim 1.

27. A photoelectric device comprising a plurality of the core/multiple shell semiconductor nanocrystals according to claim 1.

28. A laser device comprising a plurality of core/multiple shell semiconductor nanocrystals according to claim 1.

29. An optical data communication system comprising a plurality of the core/multiple shell semiconductor nanocrystals according to claim 1.

30. A host material containing a plurality of the core/multishell semiconductor nanocrystals according to claim 1.

31. The host material according to claim 30 being a polymer.

32. The host material according to claim 31, wherein said polymer is selected from fluorinated polymers, polymers of Ployacrylamide, polymers of Polyacrylic acids, polymers of Polyacrylonitrile, polymers of Polyaniline, polymers of Polybenzophenon, polymers of poly(methyl mathacrylate), silicone polymers, Aluminium polymers, polymers of Polybisphenol, polymers of Polybutadiene, polymers of Polydimethylsiloxane, polymers of Polyethylene, polymers of Polyisobutylene, polymers of Polypropylene, polymers of Polystyrene and Polyvinyl polymers.

33. The host material according to claim 32, wherein said polymer is selected from polyvinyl and fluorinated polymers.

34. The host material according to claim 33, wherein said polymer is polyvinyl-butyral or Perfluorocyclobutyl.

35. A plurality of the core/multishell semiconductor nanocrystals according to claim 1, having luminescence at a wavelength from about 400 to about 1600 nm.

5. A core/shell1/shell2 semiconductor nanocrystal comprising a core material made of a III/V compound, shell1 material and shell2 material, each made of a different compound, independently selected from II/VI, III/V or III/VI compound, wherein shell1 material coats the core material and shell2 material coats said first shell1 material;

wherein said nanocrystal exhibits luminescence at a wavelength from about 400 to about 1600 nm as measured by a NIR spectrophotometer.

6. A core/shell1/shell2 semiconductor nanocrystal comprising a core material made of a III/V compound, shell1 material and shell2 material, each made of a different compound, independently selected from II/VI, III/V or III/VI compound, wherein shell1 material coats the core material and shell2 material coats said first shell1 material;

wherein

(i) the band gap of the core material is less than the band gap of the shell1 material;

(ii) the band gap of the shell1 material is larger than the band gap of the core material and lower than the band gap of the shell2 material.

17. A method for the manufacture of a core/multishell semiconductor nanocrystal having at least two shells, comprising:

(i) providing a core,

(ii) contacting said core with a first solution of a soluble cation or soluble anion selected from Group of IIIa, IIa, Va or VIa ions, allowing said cation or anion to react on said core,

(iii) contacting the core with the counter ion, selected from Group of IIIa, IIa, Va or VIa ions, of said first soluble cation or soluble anion solution of step (ii) and allowing said counter ion to react and afford a core/shell1 structure,

(iv) contacting said core/shell1 structure with a second solution of a soluble cation or soluble anion, selected from Group of IIIa, IIa, Va or VIa ions, allowing said cation or anion to react on shell1 of said core/shell1 structure,

(v) contacting said core/shell1 structure with the counterion, selected from Group of IIIa, IIa, Va or VIa ions, of said second soluble cation or soluble anion solution of step (iv) and allowing to react and afford a core/shell1/shell2 structure,

(vi) optionally repeating steps (ii) to (v) to form a core/multishell semiconductor nanocrystal of a higher order

wherein said core/multishell is undoped and exhibits luminescence at a wavelength from about 400 to about 1600 nm.

18. The method according to claim 17, wherein said core/multishell exhibits a type-I band offset.

19. The method according to claim 17, further comprising the steps of isolating said core/shell1 and said core/shell1/shell2 structures.

20. The method according to claim 17, wherein said first soluble cation solution is selected from Cd and Zn.

21. The method according to claim 17, wherein said first soluble anion solution is selected from S, Se and P.

22. The method according to claim 17, wherein said second soluble cation solution is selected from Zn and Cd.

23. The method according to claim 17, wherein said second soluble anion solution is selected from S and Se.