# US 11,910,703 B2 · Quantum dot composition including a quantum dot, and a ligand having a head portion, a connecting portion including a metal, and a tail portion

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- Number: US 11,910,703 B2
- Document ID: US11910703B2
- Status: Granted
- Kind: B2
- Application number: 17/152,640
- Filed: 2021-01-19
- Published: 2021-12-02
- Granted: 2024-02-20
- Earliest claimed: 2020-06-02
- Assignees: Samsung Display Co., Ltd.
- Applicants: Samsung Display Co., Ltd.
- Inventors: Changhee Lee; Yunku Jung; Hyojin Ko; Dukki Kim; Sehun Kim; Jaehoon Kim; Hyunmi Doh; Jaekook Ha
- Web page: https://patentgrep.com/patent/US11910703B2

## CPC

- C09K 11/06: containing organic luminescent materials
- H10K 85/361: {Polynuclear complexes, i.e. complexes comprising two or more metal centers}
- H10K 85/381: {Metal complexes comprising a group IIB metal element, e.g. comprising cadmium, mercury or zinc}
- C09K 2211/10: Non-macromolecular compounds
- C09K 2211/188: of other metals not provided for in one of the previous groups
- H10K 50/115: comprising active inorganic nanostructures, e.g. luminescent quantum dots
- H10K 59/38: comprising colour filters or colour changing media [CCM]
- H10K 71/40: Thermal treatment, e.g. annealing in the presence of a solvent vapour
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

A quantum dot composition includes a quantum dot, and a ligand bonded to a surface of the quantum dot, wherein the ligand includes a head portion bonded to the surface of the quantum dot, a connecting portion connected to the head portion and including a metal, and a tail portion coordinated to the metal of the connecting portion. The quantum dot composition according to the present embodiments is used to form an emission layer of a light emitting element, and may thus increase service life and luminous efficiency of the light emitting element including the emission layer formed using the quantum dot composition.

## Claims

### Claim 1

A quantum dot composition comprising:
a quantum dot; and
a ligand bonded to a surface of the quantum dot,
wherein the ligand comprises:
a head portion bonded to the surface of the quantum dot;
a connecting portion connected to the head portion and comprising a metal; and
a tail portion coordinated to the metal of the connecting portion.

### Claim 2 (depends on 1)

The quantum dot composition of claim 1, wherein the head portion comprises at least one selected from a thiol group and a hydroxyl group.

### Claim 3 (depends on 1)

The quantum dot composition of claim 1, wherein the quantum dot comprises a core and a shell around the core.

### Claim 4 (depends on 1)

The quantum dot composition of claim 1, further comprising a ligand-removal agent to react with the connecting portion.

### Claim 5 (depends on 1)

The quantum dot composition of claim 1, wherein the connecting portion comprises at least one selected from Cd, Zn, In, Sn, Sb, Ga, Ge, As, Hg, Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os, Mn, Mo, and Cr.

### Claim 6 (depends on 1)

The quantum dot composition of claim 1, wherein the tail portion comprises at least one selected from (—O(O)—CNR), (—S(S)—CNR), (—O(O)—COR), (—S(S)—COR), (—O(O)— CR), (—S(S)—CR), a pyridine group, a bipyridine group, a quinoline group, a quinolinol group, a chalcogenide connecting atom selected from S, Se, and Te, an oxygen atom, and a nitrogen atom, and
R is an alkyl group having 1 to 20 carbon atoms.

### Claim 7 (depends on 1)

The quantum dot composition of claim 1, wherein the ligand is a monodentate ligand or a bidentate ligand.

### Claim 8 (depends on 1)

The quantum dot composition of claim 1, wherein the ligand is represented by Formula 1:
and
wherein in Formula 1,
T1 and T2 are each independently a thiol group or a hydroxyl group,
M1 and M2 are each independently at least one selected from Cd, Zn, In, Sn, Sb, Ga, Ge, As, Hg, Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os, Mn, Mo, and Cr,
Y1 to Y4 are each independently O or S, and
X is a substituted or unsubstituted amine group, a substituted or unsubstituted oxy group, a substituted or unsubstituted thio group, a substituted or unsubstituted ester group, a substituted or unsubstituted amide group, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms.

### Claim 9 (depends on 1)

The quantum dot composition of claim 1, further comprising an organic solvent.

### Claim 10

A light emitting element comprising:
a first electrode;
a hole transport region on the first electrode;
an emission layer on the hole transport region, the emission layer comprising a quantum dot comprising a hydrophilic group;
an electron transport region on the emission layer; and
a second electrode on the electron transport region.

### Claim 11 (depends on 10)

The light emitting element of claim 10, wherein the emission layer further comprises ligand residues comprising a metal and an organic ligand.

### Claim 12 (depends on 11)

The light emitting element of claim 11, wherein the ligand residues comprise at least one selected from Cd, Zn, In, Sn, Sb, Ga, Ge, As, Hg, Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os, Mn, Mo, and Cr.

### Claim 13 (depends on 11)

The light emitting element of claim 11, wherein the ligand residues comprise at least one selected from (—O(O)—CNR), (—S(S)—CNR), (—O(O)—COR), (—S(S)—COR), (—O(O)—CR), (—S(S)—CR), a pyridine group, a bipyridine group, a quinoline group, a quinolinol group, a chalcogenide connecting atom selected from S, Se, and Te, an oxygen atom, and a nitrogen atom, and
R is an alkyl group having 1 to 20 carbon atoms.

### Claim 14 (depends on 11)

The light emitting element of claim 11, wherein at least a part of the organic ligand is coordinated to the metal.

### Claim 15 (depends on 10)

The light emitting element of claim 10, wherein the quantum dot comprises a core and a shell around the core, and
the hydrophilic group is bonded to a surface of the quantum dot.

### Claim 16 (depends on 10)

The light emitting element of claim 10, wherein the hydrophilic group comprises at least one selected from a thiol group and a hydroxyl group.

### Claim 17

A method for manufacturing a light emitting element, the method comprising:
forming a first electrode;
forming a hole transport region on the first electrode;
forming an emission layer, the forming of the emission layer comprising providing, on the hole transport region, a quantum dot composition comprising a quantum dot composite comprising a quantum dot and a ligand bonded to a surface of the quantum dot;
forming an electron transport region on the emission layer; and
forming a second electrode on the electron transport region,
wherein the ligand comprises:
a head portion bonded to the surface of the quantum dot;
a connecting portion connected to the head portion and comprising a metal; and
a tail portion coordinated to the metal of the connecting portion.

### Claim 18 (depends on 17)

The method of claim 17, wherein the forming of the emission layer comprises:
providing the quantum dot composition to form a preliminary emission layer; and
applying heat or light to the preliminary emission layer to dissociate at least a part of the ligand bonded to the quantum dot.

### Claim 19 (depends on 18)

The method of claim 18, wherein the emission layer comprises a hydrophilic group-containing quantum dot, in which a remaining part of the ligand, except for the at least a part of the ligand dissociated from the quantum dot, is bonded to the surface of the quantum dot.

### Claim 20 (depends on 17)

The method of claim 17, wherein the connecting portion comprises at least one selected from Cd, Zn, In, Sn, Sb, Ga, Ge, As, Hg, Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os, Mn, Mo, and Cr.