Quantum-Dot Thin Film Deposition With Mixed Ligands for Uniformity

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Solution Overview

Problem

Existing methods, such as electrophoresis deposition, struggle to produce quantum-dot thin films with both great shape uniformity and good surface uniformity due to the use of quantum-dot ligands with either long or short molecular chains, leading to poor uniformity in the formed films.

Innovation Solution

A method involving a quantum-dot solution with a mixture of long-chain and short-chain ligands, controlled within specific ratios, is used to form quantum-dot thin films on an electrode substrate via electrophoresis deposition, optimizing the cohesion between particles to achieve improved uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a long-chain ligand is used, then shape uniformity is improved, but surface uniformity deteriorates

Engineering Contradiction:
Improveshape uniformityVSAvoidsurface uniformity
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The patent applies local quality by using different ligand chain lengths in different proportions to achieve different local effects: long-chain ligands provide shape uniformity through strong accumulation, while short-chain ligands provide surface uniformity through reduced cohesion. The mixed ligand system allows each component to perform its specialized function locally within the overall quantum-dot thin film structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining quantum dots with mixed ligands (both long-chain and short-chain) to create a composite ligand system. This composite approach allows the system to simultaneously exhibit both the shape-forming capability of long-chain ligands and the surface-smoothing capability of short-chain ligands, resolving the contradiction between shape uniformity and surface uniformity.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If a short-chain ligand is used, then surface uniformity is improved, but shape uniformity deteriorates

Engineering Contradiction:
Improvesurface uniformityVSAvoidshape uniformity
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The patent applies local quality by using different ligand chain lengths in different proportions to achieve different local effects: long-chain ligands provide shape uniformity through strong accumulation, while short-chain ligands provide surface uniformity through reduced cohesion. The mixed ligand system allows each component to perform its specialized function locally within the overall quantum-dot thin film structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining quantum dots with mixed ligands (both long-chain and short-chain) to create a composite ligand system. This composite approach allows the system to simultaneously exhibit both the shape-forming capability of long-chain ligands and the surface-smoothing capability of short-chain ligands, resolving the contradiction between shape uniformity and surface uniformity.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If photo etching method is used, then manufacturing process is simple, but luminescent efficiency and stability deteriorate

Engineering Contradiction:
Improveprocess simplicityVSAvoidluminescent efficiency and stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the chemical etching mechanism of photo etching with an electrophoresis-based deposition mechanism. Instead of using chemical reactions to form quantum-dot patterns, the invention uses electric field-driven movement and selective deposition of charged quantum dots, thereby preserving luminescent properties while achieving patterned film formation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If inkjet printing method is used, then manufacturing flexibility is improved, but repeatability and process time deteriorate

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidrepeatability
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical inkjet printing process with an electrophoresis-based deposition process. Instead of relying on precise mechanical positioning and droplet placement, the invention uses electric field control to achieve uniform and repeatable quantum-dot thin film formation, significantly improving process repeatability while maintaining flexibility.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method results in quantum-dot thin films with enhanced shape and surface uniformity without affecting electrical performance, thereby improving light efficiency.

Implementation Method 1

One is that quantum-dot materials with charges will move along a certain direction under an electric field

Methodology Applied
Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 2

the other is that quantum-dot materials will be selectively deposited on a certain electrode

Methodology Applied
Scientific EffectElectrophoretic Deposition: Electrophoretic Deposition

Data Source

PatentUS12522940B2Method of manufacturing quantum-dot thin film, quantum-dot substrate, and display panel
Publication Date: 2026.01.13 SHENZHEN CHINA STAR OPTOELECTRONICS SEMICON DISPLAY TECH CO LTD
  • US12522940B2 patent drawing
  • US12522940B2 patent drawing
  • US12522940B2 patent drawing

AI summary

A method of manufacturing a quantum-dot thin film, a quantum-dot substrate, and a display panel are provided. The method includes following steps: providing a quantum-dot solution, wherein the quantum-dot solution includes a quantum-dot mixture and a solvent, the quantum-dot mixture includes a plurality of quantum dots and a plurality of quantum-dot ligands, and the quantum-dot ligands include a long-chain ligand and a short-chain ligand; providing an electrode substrate, and dripping the quantum-dot solution onto the electrode substrate; and depositing the quantum-dot mixture of the quantum-dot solution on the electrode substrate by an electrophoresis deposition method to form the quantum-dot thin film on the electrode substrate. The quantum-dot ligands having different lengths of molecular chains are used to modify the quantum dots to reduce adhesion between particles. The quantum-dot thin film manufactured by electrophoresis deposition has great shape uniformity and good surface uniformity.