Quantum Dot Display Layer Structure to Prevent Leakage
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Solution Overview
Problem
The formation of a light-emitting layer in self-emission display devices using a drop method often results in non-uniform distribution of quantum dots, leading to exposure of hole transport material, which can cause electrical contact and leakage, thereby reducing light emission efficiency and degrading display performance.
Innovation Solution
A display device design that includes a first hole transport layer containing quantum dots coordinated with ligands, preventing exposure of the hole transport material to the light-emitting layer, and a manufacturing method involving a mixed solution forming, dropping, phase separation, exposure, and patterning steps to ensure accurate layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light-emitting layer is formed using a drop method, then manufacturing cost and ease of manufacture are improved, but manufacturing precision and reliability deteriorate due to non-uniform quantum dot distribution and coffee ring effect
Solution Approach 1:
The patent introduces a hole transport layer as an intermediary between the first electrode and the light-emitting layer. This intermediate layer prevents direct contact between the electrode and quantum dots, reducing the harmful coffee ring effect and enabling more uniform quantum dot distribution even when using simple drop methods for manufacturing
Solution Approach 2:
The patent modifies the formation process by controlling the drying conditions and layer formation parameters. By adjusting parameters such as solvent evaporation rate and layer thickness, the patent achieves uniform quantum dot distribution while maintaining the simplicity of drop-based manufacturing methods
2Ease of manufacture
If quantum dots are distributed non-uniformly in the light-emitting layer, then ease of manufacture is improved, but light emission efficiency and reliability deteriorate due to electrical contact and leakage
Solution Approach 1:
The hole transport layer serves as a protective intermediary that prevents electrical contact between the first electrode and quantum dots. This intermediate barrier eliminates leakage paths while allowing the manufacturing process to remain simple and cost-effective
Solution Approach 2:
The patent applies protective measures in advance by forming the hole transport layer before depositing the light-emitting layer. This preemptive approach prevents potential electrical contact and leakage issues before they can occur, ensuring reliable device operation
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
Prevents electrical contact and leakage, maintaining high light emission efficiency and display performance by using a ligand-coordinated quantum dot and hole transport layer structure, even when formed using a drop method.
Implementation Method 1
the light-emitting layer contains a quantum dot and a ligand coordinating with the quantum dot... the ligand coordinates with the quantum dot so as to prevent the hole transport material from being exposed to the light-emitting layer
Implementation Method 2
the plurality of light-emitting elements being configured to emit mutually different colors of light... the quantum dots within the light-emitting layer do not emit light
Data Source
AI summary
A display device has a light-emitting element layer including a plurality of light-emitting elements each of which includes a first electrode, a function layer, and a second electrode, and that emit mutually different colors of light. The function layer includes a first hole transport layer, a light-emitting layer provided on the first hole transport layer, and an electron transport layer provided on the light-emitting layer. The first hole transport layer contains a hole transport material, and the light-emitting layer contains a quantum dot and a ligand coordinating with the quantum dot. The first hole transport layer contains the quantum dot coordinating with the ligand, and the ligand coordinates with the quantum dot so as to prevent the hole transport material from being exposed to the light-emitting layer.