Quantum dot ink

• US 10,311,994 B2
• Filed: 12/29/2015
• Issued: 06/04/2019
• Est. Priority Date: 07/21/2015
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: He, Xiaolong, Yao, Qi, Yoo, Seongyeol, Shu, Shi, Cao, Zhanfeng, Xu, Wei
• Primary Examiner(s): Kopec, Mark
• Assistant Examiner(s): Diaz, Matthew R
• Application Number:
  US15/118,234
• Publication Number:
  US 20170174921A1
• Time in Patent Office: 1,253 Days
• CPC Class Codes: C09D 11/322 Pigment inks
• CPC Class Codes: C09D 11/36 based on non-aqueous solvents
• CPC Class Codes: C09D 11/38 characterised by non-macromolecular additives other than solvents, pigments or dyes
• CPC Class Codes: C09D 11/50 Sympathetic, colour changing or similar inks
• CPC Class Codes: C09D 11/52 Electrically conductive inks
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/70 containing phosphorus
• CPC Class Codes: C09K 11/7492 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/876 with zinc or cadmium
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: H01B 1/20 Conductive material dispersed in non-conductive organic material organic macromolecular compounds or compositions C08
• CPC Class Codes: H10K 50/115 comprising active inorganic nanostructures, e.g. luminescent quantum dots
• CPC Class Codes: H10K 50/15 Hole transporting layers
• CPC Class Codes: H10K 50/16 Electron transporting layers
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 71/135 using ink-jet printing
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/633 comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom
• CPC Class Codes: H10K 85/636 comprising heteroaromatic hydrocarbons as substituents on the nitrogen atom
• CPC Class Codes: H10K 85/654 comprising only nitrogen as heteroatom H10K85/652 takes precedence
• CPC Class Codes: H10K 85/656 : comprising two or more different heteroatoms per ring H10K85/652 takes precedence
• CPC Class Codes: H10K 85/6565 : Oxadiazole compounds
• CPC Class Codes: H10K 85/6572 : comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole

Abstract

A quantum dot ink, a manufacturing method thereof and a quantum dot light emitting diode device are provided. The quantum dot ink includes a non-polar organic solvent, a surface tension modifier and a hydrophobic quantum dot, the quantum dot ink further includes a carrier transport material, wherein phase separation is present between the hydrophobic quantum dot and the carrier transport material. After completing ink-jet printing the quantum dot ink, phase separation occurs between the hydrophobic quantum dot and the carrier transport material. Thus, the two-layer structure of a hydrophobic quantum dot layer and a carrier transport material layer is formed through one process. Not only a quantum dot light emitting device is manufactured by the method of ink-jet printing, but also the operation is simplified, and the manufacturing cost of the quantum dot light emitting device is reduced.

Claims

1. A quantum dot ink, comprising a non-polar organic solvent, a surface tension modifier and a hydrophobic quantum dot,

wherein the quantum dot ink further comprises a carrier transport material, and phase separation is present between the hydrophobic quantum dot and the carrier transport material;

a viscosity of the quantum dot ink is from 10 cP to 12 cP, and a surface tension of the quantum dot ink is from 32 dynes/cm to 42 dynes/cm;

a mass percentage of each component in the quantum dot ink is;

5%-15% carrier transport material, 1%-5% surface tension modifier, 2%-20% hydrophobic quantum dot and 60%-92% non-polar organic solvent,

the surface tension modifier is an organic acid, an organic ammonia or a mixture thereof.

2. The quantum dot ink according to claim 1, wherein the surface tension modifier is a hydrophobic and polar organic compound with a relative molecular mass less than 500.

3. The quantum dot ink according to claim 1, wherein the carrier transport material is an electron transport material or a hole transport material with a relative molecular mass less than 500.

4. The quantum dot ink according to claim 1, wherein the non-polar organic solvent is a liquid at 25°

C., and the boiling point is less than 200°

C. under normal pressure.

5. The quantum dot ink according to claim 1, wherein a material of the hydrophobic quantum dot is one or more selected from the group consisting of:

CdS, CdSe, CdTe, ZnO, ZnS, ZnSe, ZnTe, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InSb, AlAs, AlP, CuInS, CuInSe and AlSb.

6. The quantum dot ink according to claim 1, wherein the carrier transport material is an electron transport material, and the electron transport material is selected from the group consisting of:

Oxadiazole, Thiadiazole, S-Triazole, Naphthaline, Benzoquinone, Carbazole, derivatives of the above substances and combinations thereof.

7. The quantum dot ink according to claim 1, wherein the carrier transport material is a hole transport material, and the hole transport material is selected from the group consisting of:

CBP (4,4′

-Bis(N-carbazolyl)-1,1′

-biphenyl), a-NPD (N′

-diphenyl-N,N′

-bis(1-naphthyl)-(1,1′

-biphenyl)-4,4″

-diamine), TCCA (4,4′

,4″

-Tris(N-pyrazolyl)-triphenylamine), DNTPD(N,N′

-bis(4-(N,N′

-biphenyl-amide) phenyl)-N,N′

-Diphenylbenzidine) and combinations thereof.

8. The quantum dot ink according to claim 1, wherein the organic acid is a fatty acid, and the organic ammonia is an alkyl ammonia.

9. The quantum dot ink according to claim 8, wherein the fatty acid is selected from the group consisting of octanoic acid, decanoic acid, oleic acid, lauric acid and combinations thereof.

10. The quantum dot ink according to claim 8, wherein the alkyl ammonia is selected from the group consisting of laurylamine, hexadecylamine, octadecylamine, oleylamine and combinations thereof.

11. The quantum dot ink according to claim 1, wherein the non-polar organic solvent is selected from the group consisting of chain alkanes, cycloalkanes, halogenated hydrocarbon, aromatic hydrocarbon, derivatives of these substances and combinations thereof.

12. The quantum dot ink according claim 11, wherein the non-polar organic solvent is selected from the group consisting of n-pentane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, chloroform, ethyl bromide, carbon tetrachloride, benzene, toluene and combinations thereof.

13. The quantum dot ink according to claim 1, wherein a mass percentage of each component in the quantum dot ink is:

8%-12% carrier transport material, 1%-5% surface tension modifier, 5%-18% hydrophobic quantum dot, and 66%-86% non-polar organic solvent.

14. The quantum dot ink according to claim 1, wherein a mass percentage of each component is:

9%-11% carrier transport material, 1%-2% surface tension modifier, 10%-15% hydrophobic quantum dot, and 62%-80% non-polar organic solvent.

15. The quantum dot ink according to claim 1, wherein a surface of the hydrophobic quantum dot comprises a trioctylphosphine ligand or a trioctylphosphine oxide ligand.

16. A fabricating method of a quantum dot ink, comprising:

mixing a hydrophobic quantum dot, a carrier transport material, a surface tension modifier and a non-polar organic solvent to obtain a quantum dot ink;

wherein a proportion of each component is adjusted to allow phase separation to happen between the hydrophobic quantum dot and the carrier transport material;

a viscosity of the quantum dot ink is from 10 cP to 12 cP, and the surface tension of the quantum dot ink is from 32 dynes/cm to 42 dynes/cm;

a mass percentage of each component in the quantum dot ink is;

5%-15% carrier transport material, 1%-5% surface tension modifier, 2%-20% hydrophobic quantum dot and 60%-92% non-polar organic solvent,

the surface tension modifier is an organic acid, and organic ammonia or a mixture thereof.