Quantum Dot Ligand Mesh Formation for Photolithographic QLED Pixels

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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 nano-particle characteristics of quantum dots, making it difficult to form films through evaporation or inkjet printing.

Innovation Solution

A quantum dot ligand system is developed, comprising a coordination group and a saturated 3- to 5-membered heterocyclic group, which forms a mesh structure through cross-linking reactions facilitated by a photo acid generator, enabling high-resolution patterning via photolithography.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If evaporation or inkjet printing is used to form quantum dot films, then the inorganic nano-particle characteristics of quantum dots are maintained, but high resolution patterning cannot be achieved

Engineering Contradiction:

Improvepatterning resolutionVSAvoidfilm formation process

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the chemical parameters of the quantum dot surface by introducing organic ligands with specific functional groups (carboxylic acid, phosphonic acid, sulfonic acid groups). These parameter changes enable the quantum dots to be processed using photolithography techniques, achieving high-resolution patterning while maintaining the inorganic core characteristics.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by combining inorganic quantum dot cores with organic ligand shells. This composite material approach allows the quantum dots to maintain their inorganic properties while acquiring the processability and patterning capabilities of organic materials through the ligand functional groups.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If conventional ligands are used on quantum dots, then the quantum dot stability is maintained, but high-resolution patterning through photolithography is not enabled

Engineering Contradiction:

Improvepatterning resolutionVSAvoidquantum dot stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the functional groups at different locations on the ligand structure. The ligand has a head group that binds to the quantum dot surface (maintaining stability) and terminal functional groups (carboxylic acid, phosphonic acid, sulfonic acid) that provide photolithography reactivity (enabling patterning). This spatial differentiation of functions resolves the contradiction between stability and patterning capability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent designs universal ligands that perform multiple functions simultaneously: they provide quantum dot stabilization through surface binding, enable photolithography processing through acid-functional groups, and facilitate crosslinking through the Z group. This multi-functionality allows a single ligand structure to resolve multiple contradictory requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Manufacturing precision

If inkjet printing is used for quantum dot deposition, then the inorganic nano-particle characteristics are preserved, but difficult to achieve high resolution

Engineering Contradiction:

ImproveresolutionVSAvoidmaterial utilization efficiency

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent replaces the mechanical inkjet printing system with a chemical photolithography system. Instead of relying on mechanical deposition control, the invention uses photoacid generator-mediated chemical reactions to define patterns. This substitution enables higher resolution by using optical diffraction limits rather than mechanical print head limitations, while improving material utilization through controlled crosslinking and development processes.

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

This system allows for the production of high-resolution QLED products, improving yield and facilitating large-scale industrialization by forming red, green, and blue sub-pixels directly, thus overcoming the limitations of inkjet printing.

Implementation Method 1

performing an exposure treatment, so that the photo acid generator generates hydrogen ions and catalyzes ring-opening of the Z group for cross-linking reaction

Methodology Applied

Scientific EffectPhotolysis: Photodissociation

Implementation Method 2

The X group is a coordination group configured to form a coordination bond with a surface of a quantum dot

Methodology Applied

Scientific EffectCoordination bonding: Chemical Bonding

Data Source

PatentUS12588406B2Quantum dot ligand, quantum dot-ligand system and quantum dot material

Publication Date: 2026.03.24 BEIJING BOE TECH DEV CO LTD

AI summary

The present disclosure provides a quantum dot ligand, a quantum dot-ligand system and a quantum dot material, belonging to the field of display technology. The quantum dot ligand includes an X group, a Y group and a Z group. The Y group is configured to provide at least two binding sites, among which at least one binding site is configured to bind with the X group, and the remaining binding site is configured to bind with the Z group. The X group is a coordination group configured to form a coordination bond with a surface of a quantum dot. The Z group is a saturated 3- to 5-membered heterocyclic group containing O or S.