# US 12,765,254 B2 · Quantum dot complex having defined surface-bound ligand percentages and display device including the quantum dot complex

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- Number: US 12,765,254 B2
- Document ID: US12765254B2
- Status: Granted
- Kind: B2
- Application number: 18/448,412
- Filed: 2023-08-11
- Published: 2024-05-23
- Granted: 2026-10-13
- Earliest claimed: 2022-11-03
- Assignees: Samsung Display Co., Ltd.
- Applicants: Samsung Display Co., Ltd.
- Inventors: Seunghee Jang; Jaebok Chang; Juo Nam; Kawon Pak; Kyungsig Lee
- Web page: https://patentgrep.com/patent/US12765254B2

## CPC

- H10K 85/151: {Copolymers}
- C09K 11/02: Use of particular materials as binders, particle coatings or suspension media therefor
- C09K 11/06: containing organic luminescent materials
- C09K 11/70: containing phosphorus
- H10H 20/8513: {having two or more wavelength conversion materials}
- H10H 20/8514: {characterised by their shape, e.g. plate or foil}
- H10K 85/141: {comprising aliphatic or olefinic chains, e.g. poly N-vinylcarbazol, PVC or PTFE}
- C09K 2211/10: Non-macromolecular compounds
- H10H 20/0361: {of wavelength conversion means}
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

Embodiments provide a quantum dot complex that includes a quantum dot, and ligands bonded to a surface of the quantum dot, wherein the ligands include a first ligand including a first acid functional group, a second ligand including a second acid functional group and different from the first acid functional group, and a third ligand including a thiol group, wherein a sum of the first ligand and the second ligand contained in the ligands is in a range of 40% by weight to 45% by weight, based on a total weight of the ligands, and a content of the third ligand in the ligands is in a range of 15% by weight to 20% by weight, based on the total weight of the ligands.

## Claims

### Claim 1

A quantum dot complex comprising:
a quantum dot; and
a plurality of ligands binding to a surface of the quantum dot, wherein
the plurality of ligands include:
a first ligand including a first acid functional group;
a second ligand including a second acid functional group different from the first acid functional group; and
a third ligand including a thiol group,
a sum of the first ligand and the second ligand contained in the plurality of ligands is in a range of 40% by weight to 45% by weight, based on a total weight of the plurality of ligands binding to the surface of the quantum dot,
a content of the third ligand in the plurality of ligands is in a range of 15% by weight to 20% by weight, based on the total weight of the plurality of ligands binding to the surface of the quantum dot.

### Claim 2 (depends on 1)

The quantum dot complex of claim 1, wherein the plurality of ligands further include a basic ligand including a non-polar functional group.

### Claim 3 (depends on 1)

The quantum dot complex of claim 1, wherein each of the first acid functional group, the second acid functional group, and the thiol group binds to the surface of the quantum dot.

### Claim 4 (depends on 1)

The quantum dot complex of claim 1, wherein
the first ligand includes a first main body linked to the first acid functional group,
the second ligand includes a second main body linked to the second acid functional group, and
the first main body and the second main body are different from each other.

### Claim 5 (depends on 1)

The quantum dot complex of claim 1, wherein the third ligand includes a third main body linked to the thiol group.

### Claim 6 (depends on 1)

The quantum dot complex of claim 1, wherein the first ligand is represented by Chemical Formula 1:
wherein in Chemical Formula 1,
Y1 is the first acid functional group,
R1 is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and
n1 is an integer from 1 to 10.

### Claim 7 (depends on 1)

The quantum dot complex of claim 1, wherein the second ligand is represented by Chemical Formula 2:
wherein in Chemical Formula 2,
Y2 is the second acid functional group, and
R2 is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms.

### Claim 8 (depends on 1)

The quantum dot complex of claim 1, wherein the third ligand is represented by Chemical Formula 3:
wherein in Chemical Formula 3,
R3 is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and
n2 is an integer from 1 to 10.

### Claim 9 (depends on 1)

The quantum dot complex of claim 1, wherein
the quantum dot includes a core, and a shell surrounding the core, and
each of the plurality of ligands binds to a surface of the shell.

### Claim 10 (depends on 9)

The quantum dot complex of claim 9, wherein
the core includes a first semiconductor nanocrystal,
the shell includes a second semiconductor nanocrystal different from the first semiconductor nanocrystal, and
the first semiconductor nanocrystal and the second semiconductor nanocrystal are each independently a Group II-VI compound, a Group III-VI compound, a Group I-III-VI compound, a Group III-V compound, a Group III-II-V compound, a Group IV-VI compound, a Group IV element, a Group IV compound, or a combination thereof.

### Claim 11 (depends on 9)

The quantum dot complex of claim 9, wherein the core includes InP or AgInGaS.

### Claim 12 (depends on 1)

The quantum dot complex of claim 1, wherein a molecular weight of each of the plurality of ligands is in a range of 200 to 400.

### Claim 13 (depends on 1)

The quantum dot complex of claim 1, wherein
a content of the first ligand in the plurality of ligands is in a range of 10% by weight to 15% by weight, based on the total weight of the plurality of ligands, and
a content of the second ligand in the plurality of ligands is in a range of 25% by weight to 35% by weight, based on the total weight of the plurality of ligands.

### Claim 14 (depends on 1)

The quantum dot complex of claim 1, wherein
the quantum dot complex has a light maintaining percentage in a range of 90% to 105%, and
the light maintaining percentage is expressed based on Equation 1:
light
⁢
maintaining
⁢
percentage
⁢
(
%
)
=
X
1
/
X
0
*
100
[
Equation
⁢
1
]
wherein in Equation 1,
X1 is a quantum yield measured after irradiating the quantum dot complex with 460 nm excitation light at an intensity of 60 mW/cm2 for 500 hours, and
X0 is a quantum yield measured before irradiating the quantum dot complex with the excitation light.

### Claim 15

A display device comprising:
a display panel; and
a light control layer disposed on the display panel, the light control layer including a plurality of light control areas, wherein
at least one of the plurality of light control areas includes a quantum dot complex,
the quantum dot complex includes:
a quantum dot; and
a plurality of ligands binding to a surface of the quantum dot,
the plurality of ligands include:
a first ligand including a first acid functional group;
a second ligand including a second acid functional group different from the first acid functional group; and
a third ligand including a thiol group,
a sum of the first ligand and the second ligand contained in the plurality of ligands is in a range of 40% by weight to 45% by weight, based on a total weight of the plurality of ligands, and
a content of the third ligand in the plurality of ligands is in a range of 15% by weight to 20% by weight, based on the total weight of the plurality of ligands.

### Claim 16 (depends on 15)

The display device of claim 15, wherein
the display panel includes a light-emitting element emitting a first light, and
the light control layer includes:
a first light control area transmitting the first light therethrough;
a second light control area converting the first light into a second light; and
a third light control area converting the first light into a third light.

### Claim 17 (depends on 15)

The display device of claim 15, further comprising a color filter layer disposed on the light control layer,
wherein the color filter layer includes a first filter, a second filter, and a third filter respectively corresponding to the first light control area, the second light control area, and the third light control area.