Group IV nanocrystals with ion-exchangeable surface ligands and methods of making the same

Patent metadata

Field	Value
Publication number	US-9862841-B2
Application number	US-201615388415-A
Country	US
Kind code	B2
Filing date	Dec 22, 2016
Priority date	Dec 24, 2015
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

Methods are described that include reacting a starting nanocrystal that includes a starting nanocrystal core and a covalently bound surface species to create an ion-exchangeable (IE) nanocrystal that includes a surface charge and a first ion-exchangeable (IE) surface ligand ionically bound to the surface charge, where the starting nanocrystal core includes a group IV element.

First claim

What is claimed is:

1. A method comprising:
contacting a starting nanocrystal with a precursor of a first ligand and at least one of an oxidizing agent or a reducing agent, wherein:
the starting nanocrystal comprises a core having an outer surface and a starting ligand covalently bound to the outer surface,
the contacting results in a removal of at least a portion of the starting ligand from the core and the formation of a first charge on the outer surface,
the contacting results in the formation of the first ligand having a second charge opposite to the first charge,
the second charge associates with the first charge to form a first nanocrystal comprising the first ligand ionically bound to the core, and
the first ligand is capable of being reversibly exchanged with a second ligand to form a second nanocrystal comprising the second ligand ionically bound to the core.

2. The method of claim 1 , wherein the core comprises a group IV element.

3. The method of claim 2 , wherein the group IV element comprises germanium.

4. The method of claim 1 , wherein the starting ligand comprises at least one of hydrogen, a saturated hydrocarbon, an unsaturated hydrocarbon, a halogen, or a chalcogen.

5. The method of claim 1 , wherein the first charge is negative.

6. The method of claim 5 , wherein the first ligand comprises at least one of an alkylammonium, a phosphonium, a hydrazinium, or an alkali metal.

7. The method of claim 6 , wherein the first ligand comprises at least one of oleylammonium, CH 3 (CH 2 ) 11 NH 3 + , CH 3 NH 3 + , N 2 H 5 + , or Na + .

8. The method of claim 1 , wherein the first charge is positive.

9. The method of claim 8 , wherein the first ligand comprises at least one of BF 4 − , ClO 4 − , PF 6 − , (C 6 H 5 ) 4 B − , or (C 6 F 5 ) 4 B − .

10. The method of claim 1 , wherein the contacting removes substantially all of the starting ligand.

11. The method of claim 1 , wherein the reducing agent comprises at least one of a sulfide, an alkali metal, an alkaline earth metal, an alkyllithium reagent, a Grignard reagent, a metal hydride, sodium borohydride, or dihydrogen.

12. The method of claim 1 , wherein the oxidizing agent comprises at least one of NOBF 4 , [(CH 3 CH 2 ) 3 O][BF 4 ], an elemental halide, or an elemental chalcogen.

13. The method of claim 1 , wherein the precursor of the first ligand comprises at least one of an alkali metal salt, oleylamine, hydrazine, ammonia, an amine, or a phosphine.

14. The method of claim 1 , further comprising:
an additional contacting of the first nanocrystal with a precursor of the second ligand, wherein:
the additional contacting results in the forming of the second nanocrystal, and
the second ligand is different from the first ligand.

15. A nanoparticle comprising:
a core comprising a group IV element and an outer surface having a surface charge; and
a first ligand comprising a charge opposite of the surface charge, wherein:
the first ligand is ionically bound to the core, and
at least a portion of the first ligand is capable of being reversibly exchanged with a second ligand.

16. The nanoparticle of claim 15 , wherein the group IV element comprises germanium.

17. The nanoparticle of claim 15 , wherein:
the first ligand comprises at least one of oleylammonium, Na + , NR x H y + , or PR' v H w + , and
R is a first organic group, R' is a second organic group, y=4−x, and w=4−v.

18. The nanoparticle of claim 15 , wherein the first ligand comprises at least one of BF 4 − , ClO 4 − , PF 6 − , (C 6 H 5 ) 4 B − , or (C 6 F 5 ) 4 B − .

Assignees

• Alliance Sustainable Energy

Inventors

• Wheeler Lance M
• Nichols Asa W
• Chernomordik Boris D
• Anderson Nicholas C
• Beard Matthew C
• Neale Nathan R

Classifications

• H01L31/1808

  Electricity · mapped topic

• H01L31/035218

  Electricity · mapped topic

• C09D5/32

  Radiation-absorbing paints {(protection against X-, gamma- or corpuscular radiation G21F)} · CPC title

• H01L31/028

  Electricity · mapped topic

• H01L31/1884

  Electricity · mapped topic