Quantum Dot Ligand Photodissociation for High-Resolution QLED Patterning

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Solution Overview

Problem

The high-resolution patterning technology for Quantum Dot Light Emitting Diodes (QLEDs) has not yet been achieved due to the inorganic nanoparticle characteristics of quantum dots, making it difficult to form films by evaporation and inkjet printing.

Innovation Solution

A quantum dot ligand with a structural formula X-Y-Z, where X is a coordination group, Y is a linking and photosensitive group, and Z is a dissolving group, allowing the ligand to decompose into units with different polarities under light conditions, enabling photolithographic formation of quantum dot film layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If evaporation method is used to form quantum dot film, then film formation is possible, but high-resolution patterning cannot be achieved due to inorganic nanoparticle characteristics

Engineering Contradiction:
Improvepatterning resolutionVSAvoidfilm formation process
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent introduces an organic ligand as an intermediary substance between the inorganic quantum dot nanoparticles and the patterning process. This ligand mediates the interaction by providing functional groups that enable photolithographic patterning while maintaining the quantum dot film structure, thus resolving the contradiction between achieving high-resolution patterning and maintaining ease of manufacture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical parameters of the quantum dot surface by attaching ligands with specific functional groups (photosensitive groups, coordinating groups, dissolving groups). This parameter change enables the quantum dots to respond to photolithography processes while maintaining their nanoparticle characteristics, allowing high-resolution patterning without compromising the film formation process.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If inkjet printing method is used for quantum dot patterning, then film formation is possible, but high resolution cannot be achieved

Engineering Contradiction:
Improvepatterning resolutionVSAvoidprocess efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical inkjet printing system with a photolithographic system. By introducing ligands with photosensitive groups, the quantum dot film can be patterned through light-induced chemical reactions rather than mechanical deposition, achieving high-resolution patterning while maintaining process efficiency through parallel processing capabilities of photolithography.

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

3Manufacturing precision

If photolithography process is implemented without specific ligand design, then high-resolution patterning may be achieved, but quantum dot film formation and material utilization are compromised

Engineering Contradiction:
Improvepatterning resolutionVSAvoidquantum dot material utilization rate
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent segments the ligand molecule into distinct functional groups (coordinating group, photosensitive group, dissolving group) that perform specific functions. The coordinating group binds to quantum dots, the photosensitive group enables patterning, and the dissolving group controls solubility. This segmentation allows each component to optimize its function, achieving high-resolution patterning while minimizing quantum dot material loss through controlled decomposition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different functional properties to different parts of the ligand molecule. The coordinating group provides strong binding to quantum dots, the photosensitive group provides light-responsive patterning capability, and the dissolving group provides solubility control. This local quality differentiation enables the ligand to simultaneously achieve high-resolution patterning and high material utilization by controlling where and how quantum dots decompose.

Inventive Principle:
Principle #3Local quality

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

Enables high-resolution patterning of quantum dot film layers, improving process yields and material utilization, facilitating large-scale industrialization of QLEDs.

Implementation Method 1

the photosensitive group is capable of undergoing bond breaking under light condition such that the quantum dot ligand decomposes into a first unit including the coordination group and the linking group, and a second unit including the dissolving group

Methodology Applied
Scientific EffectPhotodissociation: Photodissociation

Data Source

PatentEP4394015B1Quantum dot ligand, preparation method for quantum dot film layer, and quantum dot light emitting device
Publication Date: 2026.04.22 BOE TECHNOLOGY GROUP CO LTD
  • EP4394015B1 patent drawingFigure 1~6
  • EP4394015B1 patent drawingFigure 7~8
  • EP4394015B1 patent drawing

AI summary

A quantum dot ligand, a preparation method for a quantum dot film layer, and a quantum dot light emitting device, which belong to the technical field of display. The structural general formula of the quantum dot ligand is shown as formula I, X-Y-Z formula I, wherein X is a coordination group for forming a coordinate bond with a quantum dot body; Z is a soluble group, and the soluble group is selected from polar groups; Y comprises a connecting group and a photosensitive group that are connected with each other, and the connecting group is connected between the coordination group and the photosensitive group; the connecting group is selected from alkylene; the photosensitive group can lead to bond breaking under illumination, breaking up the quantum dot ligand into a first unit comprising the coordination group and the connecting group, and a second unit comprising the soluble group. The polarity of the first unit is smaller than that of the second unit, which provides a basis for enabling the formation of a quantum dot film layer using a photo etching process.