Quantum dots with charge-transporting ligands

1. A nanostructure composition comprising:

(a) at least one population of nanostructures; and

(b) at least one charge-transporting ligand bound to the surface of the nanostructures, the charge-transporting ligand comprising:

(i) a hole-transporting ligand of formula (I)

wherein:

R 1 is hydrogen or carboxy;

R 2 is

R 3 is hydrogen;

X 1 -X 8 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

X 9 -X 13 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 4 is an unsubstituted or substituted aryl or heteroaryl group;

X 14 -X 17 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 5 is an unsubstituted or substituted aryl or heteroaryl group;

R 6 is hydrogen; or

R 5 and R 6 together form:

X 18 -X 22 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 7 is an unsubstituted or substituted aryl or heteroaryl group; or

R 2 and R 3 together form:

X 23 -X 26 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 8 is an unsubstituted or substituted aryl or heteroaryl group;

R 9 is an unsubstituted or substituted aryl or heteroaryl group;

R 10 is hydrogen or an unsubstituted or substituted aryl or heteroaryl group; or

R 9 and R 10 together form:

or

(ii) an electron-transporting ligand of formula (X)

wherein:

R 11 is

R 12 is hydrogen or is

R 13 and R 17 independently are a substituted or unsubstituted aryl or heteroaryl group;

R 14 and R 18 independently are hydrogen, or

R 15 and R 19 independently are a substituted or unsubstituted aryl or heteroaryl group;

R 16 and R 20 independently are a substituted or unsubstituted aryl or heteroaryl group;

R 21 is a substituted or unsubstituted aryl or heteroaryl group;

R 22 is a substituted or unsubstituted aryl or heteroaryl group;

R 23 is H or a substituted or unsubstituted aryl or heteroaryl group; and

R 24 is H or a substituted or unsubstituted aryl or heteroaryl group;

or

(iii) a combination thereof.

2. The nanostructure composition of claim 1 , wherein the nanostructures comprise a core selected from the group consisting of InP, InZnP, InGaP, CdSe, CdS, CdSSe, CdZnSe, CdZnS, ZnSe, ZnTe, ZnSeTe, ZnS, ZnSSe, InAs, InGaAs, and InAsP.

3. The nanostructure composition of claim 1 , wherein the nanostructures comprises an InP core, a ZnSe shell, and a ZnS shell.

4. The nanostructure composition of claim 1 , wherein the hole-transporting ligand has formula II:

wherein:

X 1 -X 8 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl; and

R 1 is hydrogen or carboxy.

5. The nanostructure composition of claim 4 , wherein X 1 , X 2 , X 4 , X 5 , X 7 , and X 8 are hydrogen, X 3 and X 6 independently are hydrogen, methyl, tert-butyl, methoxy, dimethylamino, or trifluoromethyl, and R 1 is hydrogen.

6. The nanostructure composition of claim 1 , wherein the hole-transporting ligand has the structure of formula III:

wherein:

X 9 -X 13 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 1 is hydrogen or carboxy; and

R 4 is an unsubstituted or substituted aryl or heteroaryl group.

7. The nanostructure composition of claim 1 , wherein the hole-transporting ligand has the structure of formula IV:

wherein:

X 14 -X 17 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 1 is hydrogen or carboxy;

R 5 is an unsubstituted or substituted aryl or heteroaryl group; and

R 6 is hydrogen.

8. The nanostructure composition of claim 1 , wherein the hole-transporting ligand has the structure of formula V:

wherein:

X 14 -X 17 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl; and

R 1 is hydrogen or carboxy.

9. The nanostructure composition of claim 1 , wherein the hole-transporting ligand has the structure of formula VI:

wherein:

X 18 -X 22 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 1 is hydrogen or carboxy; and

R 7 is an unsubstituted or substituted aryl or heteroaryl group.

10. The nanostructure composition of claim 1 , wherein the hole-transporting ligand has the structure of formula VII:

wherein:

X 23 -X 26 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 1 is hydrogen or carboxy; and

R 8 is an unsubstituted or substituted aryl or heteroaryl group.

11. The nanostructure composition of claim 1 , wherein the hole-transporting ligand has the structure of formula VIII:

wherein:

R 1 is hydrogen or carboxy; and

R 9 is an unsubstituted or substituted aryl or heteroaryl group; and

R 10 is an unsubstituted or substituted aryl or heteroaryl group.

12. The nanostructure composition of claim 1 , wherein the hole-transporting ligand has the structure of formula IX:

wherein:

R 1 is hydrogen or carboxy.

13. The nanostructure composition of claim 1 , wherein the electron-transporting ligand has the structure of formula XII:

14. The nanostructure composition of claim 1 , wherein the electron-transporting ligand has the structure of formula XIII:

wherein:

R 14 is a substituted or unsubstituted aryl or heteroaryl group.

15. The nanostructure composition of claim 1 , wherein the electron-transporting ligand has the structure of formula XIV:

wherein:

R 17 is a substituted or unsubstituted aryl or heteroaryl group.

16. The nanostructure composition of claim 15 , wherein R 17 is an unsubstituted phenyl group.

17. The nanostructure composition of claim 1 , wherein the electron-transporting ligand has the structure of formula XV:

wherein:

R 18 is a substituted or unsubstituted aryl or heteroaryl group.

18. The nanostructure composition of claim 1 , wherein the electron-transporting ligand has the structure of formula XVI:

wherein:

R 19 is a substituted or unsubstituted aryl or heteroaryl group; and

R 20 is a substituted or unsubstituted aryl or heteroaryl group.

19. The nanostructure composition of claim 1 , wherein the electron-transporting ligand has the structure of formula XVIII:

wherein:

R 14 is a substituted or unsubstituted aryl or heteroaryl group; and

R 15 is a substituted or unsubstituted aryl or heteroaryl group.

20. A nanostructure film layer comprising the nanostructure composition of claim 1 .

21. The nanostructure film layer of claim 20 , wherein the at least one population of nanostructures comprises a core selected from the group consisting of InP, InZnP, InGaP, CdSe, CdS, CdSSe, CdZnSe, CdZnS, ZnSe, ZnTe, ZnSeTe, ZnS, ZnSSe, InAs, InGaAs, and InAsP.

22. A method of replacing a first ligand on a nanostructure with a second ligand, the method comprising admixing a reaction mixture comprising a population of nanostructures having the first ligand bound to the nanostructure and a charge-transporting ligand which is the second ligand, such that the second ligand displaces the first ligand and becomes bound to the nanostructure, wherein the charge-transporting ligand comprises:

(i) a hole-transporting ligand of formula (I)

wherein:

R 1 is hydrogen or carboxy;

R 2 is

R 3 is hydrogen;

X 1 -X 8 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

X 9 -X 13 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 4 is an unsubstituted or substituted aryl or heteroaryl group;

X 14 -X 17 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 5 is an unsubstituted or substituted aryl or heteroaryl group;

R 6 is hydrogen; or

R 5 and R 6 together form:

X 18 -X 22 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 7 is an unsubstituted or substituted aryl or heteroaryl group;

or

R 2 and R 3 together form:

X 23 -X 26 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 8 is an unsubstituted or substituted aryl or heteroaryl group;

R 9 is an unsubstituted or substituted aryl or heteroaryl group;

R 10 is hydrogen or an unsubstituted or substituted aryl or heteroaryl group; or

R 9 and R 10 together form:

or

(ii) an electron-transporting ligand of formula (X)

wherein:

R 11 is

R 12 is hydrogen or is

R 13 and R 17 independently are a substituted or unsubstituted aryl or heteroaryl group;

R 14 and R 18 independently are hydrogen, or

R 15 and R 19 independently are a substituted or unsubstituted aryl or heteroaryl group;

R 16 and R 20 independently are a substituted or unsubstituted aryl or heteroaryl group;

R 21 is a substituted or unsubstituted aryl or heteroaryl group;

R 22 is a substituted or unsubstituted aryl or heteroaryl group;

R 23 is H or a substituted or unsubstituted aryl or heteroaryl group; and

R 24 is H or a substituted or unsubstituted aryl or heteroaryl group;

or

(iii) a combination thereof.

23. A light emitting diode comprising:

(a) a first conductive layer;

(b) a second conductive layer; and

(c) an emitting layer between the first conductive layer and the second conductive layer, wherein the emitting layer comprises at least one population of nanostructures comprising a charge-transporting ligand bound to the nanostructures, wherein the charge-transporting ligand comprises:

(i) a hole-transporting ligand of formula (I)

wherein:

R 1 is hydrogen or carboxy;

R 2 is

X 1 -X 8 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

X 9 -X 13 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 4 is an unsubstituted or substituted aryl or heteroaryl group;

X 14 -X 17 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 5 is an unsubstituted or substituted aryl or heteroaryl group;

R 6 is hydrogen; or

R 5 and R 6 together form:

X 18 -X 22 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 7 is an unsubstituted or substituted aryl or heteroaryl group;

or

R 2 and R 3 together form:

X 23 -X 26 independently are hydrogen, carboxy, C 1-10 alkyl, C 1-10 alkoxy, C 1-10 haloalkyl, halogen, C 1-10 alkylamino, or cycloalkyl;

R 8 is an unsubstituted or substituted aryl or heteroaryl group;

R 9 is an unsubstituted or substituted aryl or heteroaryl group;

R 10 is hydrogen or an unsubstituted or substituted aryl or heteroaryl group; or

R 9 and R 10 together form:

or

(ii) an electron-transporting ligand of formula (X)

wherein:

R 11 is

is hydrogen or is

R 13 and R 17 independently are a substituted or unsubstituted aryl or heteroaryl group;

R 14 and R 18 independently are hydrogen, or

R 15 and R 19 independently are a substituted or unsubstituted aryl or heteroaryl group;

R 16 and R 20 independently are a substituted or unsubstituted aryl or heteroaryl group;

R 21 is a substituted or unsubstituted aryl or heteroaryl group;

R 22 is a substituted or unsubstituted aryl or heteroaryl group;

R 23 is H or a substituted or unsubstituted aryl or heteroaryl group; and

R 24 is H or a substituted or unsubstituted aryl or heteroaryl group;

or

(iii) a combination thereof.

24. The light emitting diode of claim 23 , wherein the at least one population of nanostructures comprises a core selected from the group consisting of InP, InZnP, InGaP, CdSe, CdS, CdSSe, CdZnSe, CdZnS, ZnSe, ZnTe, ZnSeTe, ZnS, ZnSSe, InAs, InGaAs, and InAsP.

25. The light emitting diode of claim 23 , wherein the first conductive layer comprises indium tin oxide, indium zinc oxide, tin dioxide, zinc oxide, magnesium, aluminum, aluminum-lithium, calcium, magnesium-indium, magnesium-silver, silver, gold, or mixtures thereof.

26. The light emitting diode of claim 23 , wherein the second conductive layer comprises indium tin oxide, indium zinc oxide, titanium dioxide, tin oxide, zinc sulfide, silver, or mixtures thereof.

27. The light emitting diode of claim 23 , wherein the first conductive layer comprises indium tin oxide, the second conductive layer comprises aluminum, further comprising a semiconductor polymer layer, wherein the semiconductor polymer layer comprises PEDOT/PSS, further comprising a first transport layer, wherein the first transport layer comprises N,N′-di(naphthalen-1-yl)-N,N′-bis(4-vinylphenyl)-4,4′-diamine, and further comprising a second transport layer, wherein the second transport layer comprises ZnMgO.

28. The light emitting diode of claim 23 , wherein the first conductive layer comprises indium tin oxide, the second conductive layer comprises gold, further comprising a semiconductor polymer layer, wherein the semiconductor polymer layer comprises PEDOT/PSS, and further comprising a first transport layer, wherein the first transport layer comprises N,N′-di(naphthalen-1-yl)-N,N′-bis(4-vinylphenyl)-4,4′-diamine.