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CN-122011831-A - Lead salt quantum dot ink and preparation method thereof

CN122011831ACN 122011831 ACN122011831 ACN 122011831ACN-122011831-A

Abstract

The application provides lead salt quantum dot ink and a preparation method thereof, wherein the preparation method comprises the steps of preparing sulfur-containing additive solution; and adding a sulfur-containing additive solution into the short-chain halogen ligand-coated lead salt quantum dot powder within 3min after preparing the short-chain halogen ligand-coated lead salt quantum dot powder, and dissolving to obtain the lead salt quantum dot ink. The lead salt quantum dot ink prepared by the preparation method can maintain the stability of the lead salt quantum dot ink, reduce the residue of ligands in the lead salt quantum dot ink, improve the film forming property of the lead salt quantum dot ink and reduce the film surface defect of a quantum dot film.

Inventors

  • Gao Geyuan
  • WANG YUAN

Assignees

  • 杭州海康微影传感科技有限公司

Dates

Publication Date
20260512
Application Date
20260310

Claims (10)

  1. 1. The preparation method of the lead salt quantum dot ink is characterized by comprising the following steps of: Preparing a sulfur-containing additive solution, wherein the sulfur-containing additive is at least one selected from thiourea, methyl thiourea, diphenyl thiourea, pyridyl thiourea, dimethyl thiourea, polythiourea, elemental sulfur, carbon disulfide and sodium sulfide; Lead salt quantum dots wrapped by long carbon chain oil phase organic ligands are subjected to ligand exchange to obtain lead salt quantum dot powder wrapped by short chain halogen ligands; And after the lead salt quantum dot powder wrapped by the short-chain halogen ligand is prepared, adding the sulfur-containing additive solution into the lead salt quantum dot powder wrapped by the short-chain halogen ligand within 3min, and dissolving to obtain the lead salt quantum dot ink.
  2. 2. The preparation method of the sulfur-containing additive solution according to claim 1, wherein the sulfur-containing additive solution is prepared by dispersing a sulfur-containing additive in a first organic solvent, uniformly dispersing and filtering the solution to obtain the sulfur-containing additive solution, wherein the volume ratio of the molar amount of the sulfur-containing additive to the first organic solvent is 0.01-1 mmol/200-1500 mu L, and the first organic solvent is at least one selected from N, N-dimethylformamide, methanol, ethylene glycol, dimethyl sulfoxide, aniline, butylamine, methylamine and benzyl alcohol.
  3. 3. The preparation method according to claim 2, wherein the first organic solvent is a mixed solution of N, N-dimethylformamide and benzyl alcohol, and the volume ratio of N, N-dimethylformamide to benzyl alcohol is 1:1-1:12.
  4. 4. The preparation method according to claim 1, wherein the mass-to-volume ratio of the short-chain halogen ligand-coated lead salt quantum dot powder to the sulfur-containing additive solution is 60-80mg:200-1500 μl.
  5. 5. The preparation method of the lead salt quantum dot powder is characterized in that the ligand exchange step comprises the steps of adding a second organic solvent containing lead salt quantum dots coated by long carbon chain oil phase organic ligands into a first solution containing PbI 2 、PbBr 2 、NH 4 Ac, violently oscillating and layering; The ratio of the mass of the long carbon chain oil phase organic ligand coated lead salt quantum dot, the volume of the second organic solvent, the mass of the PbI 2 , the mass of the PbBr 2 and the solvent volume of the NH 4 Ac to the first solution is 100mg:20-100mL:2.3-6.9g:0.73-2.19g:0.05-0.20g:20-80mL; the second organic solvent is at least one selected from n-hexane, n-octane and n-heptane; The solvent of the first solution is at least one selected from N, N-dimethylformamide, methanol, ethylene glycol, dimethyl sulfoxide, aniline, butylamine and methylamine.
  6. 6. The preparation method of the solid-liquid separation device according to claim 5, wherein the extraction, purification and separation of the lower layer solution comprises the steps of adding a third organic solvent into the lower layer solution for extraction for 2-4 times, adding a fourth organic solvent for purification, and carrying out solid-liquid separation; the third organic solvent and the fourth organic solvent are each independently selected from at least one of isopentane, n-pentane, n-hexane, cyclohexane, n-octane, trifluoroacetic acid, n-heptane, cycloheptane, toluene.
  7. 7. The method of claim 1, wherein the dissolving step comprises shaking for 1-3min, vortexing for 3-5min, and sonicating for 1-3min.
  8. 8. A lead salt quantum dot ink made by the method of any one of claims 1-7.
  9. 9. A method for preparing a quantum dot film, characterized in that the quantum dot film is prepared by coating lead salt quantum dot ink prepared by the preparation method according to any one of claims 1 to 7 within 30 minutes after the preparation of the lead salt quantum dot ink.
  10. 10. The quantum dot film prepared by the preparation method according to claim 9.

Description

Lead salt quantum dot ink and preparation method thereof Technical Field The application relates to the technical field of quantum dot ink, in particular to lead salt quantum dot ink and a preparation method thereof. Background At present, a main stream synthesis method of the lead salt quantum dot wrapped by the long carbon chain oil phase organic ligand is a hot injection method, a lead precursor coordinated by the long carbon chain is synthesized under the environment of the long carbon chain organic ligand (hereinafter referred to as an oil-soluble ligand), then active substances containing sulfur (S) and selenium (Se) are injected, and the generated quantum dot is wrapped by the oil-soluble ligand due to the fact that a large number of long carbon chains exist in a reaction system, the oil-soluble ligand is relatively large in chain length and relatively large in steric hindrance, the quantum dot is mutually spread by the oil-soluble ligand, the dot spacing is relatively far, agglomeration phenomenon is not easy to occur due to mutual collision, but carriers generated by the excitation of the quantum dot are difficult to transport, and the conductivity is relatively poor. Therefore, although the oil-soluble ligand-coated lead salt quantum dot has good stability and is convenient to store and transport, the oil-soluble ligand-coated lead salt quantum dot is difficult to directly put into actual device production. The surface of the quantum dot material synthesized by the thermal injection method is attached with oil-soluble organic matters (such as oleic acid and oleylamine ligand), and in order to reduce the interval between the quantum dots, the originally attached oil-soluble ligand is replaced by a halogen ion ligand (such as PbI 2,PbBr2,PbCl2 and the like) through a ligand exchange process so as to increase the conductivity of the quantum dot material in photoelectric devices. However, the ligand exchange process may cause excessive ligand residues such as PbI 2、PbBr2, which cannot be effectively removed in the purification process. When the photoelectric device is prepared, residual ligand precipitation occurs in the spin-coating and drying process, a large amount of solid particles are generated, the uniformity of the quantum dot film is destroyed, the defect of the quantum dot film is caused, and the device performance is influenced. In addition, quantum dot inks are generally poor in stability, and are prone to aggregation under common process environments (e.g., 25 ℃ and 40+ -10% relative humidity) to form jelly-like colloids, which cannot be used for device preparation. Disclosure of Invention The application aims to provide lead salt quantum dot ink and a preparation method thereof, which are used for guaranteeing the stability of the lead salt quantum dot ink, reducing the residue of ligands in the lead salt quantum dot ink, improving the film forming property of the lead salt quantum dot ink and reducing the film surface defect of a quantum dot film. The specific technical scheme is as follows: The first aspect of the application provides a preparation method of lead salt quantum dot ink, which comprises the following steps: Preparing a sulfur-containing additive solution, wherein the sulfur-containing additive is at least one selected from thiourea, methyl thiourea, diphenyl thiourea, pyridyl thiourea, dimethyl thiourea, polythiourea, elemental sulfur, carbon disulfide and sodium sulfide; lead salt quantum dots wrapped by long carbon chain oil phase organic ligands are subjected to ligand exchange to obtain lead salt quantum dot powder wrapped by short chain halogen ligands; And after the lead salt quantum dot powder wrapped by the short-chain halogen ligand is prepared, adding the sulfur-containing additive solution into the lead salt quantum dot powder wrapped by the short-chain halogen ligand within 3min, and dissolving to obtain the lead salt quantum dot ink. In one embodiment, the preparation step of the sulfur-containing additive solution comprises the steps of dispersing a sulfur-containing additive in a first organic solvent, uniformly dispersing and filtering to obtain the sulfur-containing additive solution, wherein the volume ratio of the molar quantity of the sulfur-containing additive to the first organic solvent is 0.01-1 mmol/200-1500 mu L, and the first organic solvent is at least one selected from N, N-Dimethylformamide (DMF), methanol, glycol, dimethyl sulfoxide, aniline, butylamine, methylamine and Benzyl Alcohol (BA). In one embodiment, the first organic solvent is a mixed solution of N, N-dimethylformamide and benzyl alcohol, and the volume ratio of N, N-dimethylformamide to benzyl alcohol is 1:1-1:12. In one embodiment, the uniform dispersion comprises vortexing, and ultrasonic dispersion for 10-20min. In one embodiment, the mass to volume ratio of the short-chain halogen ligand-coated lead salt quantum dot powder to the sulfur-containing additive solution is 60-80 m