Ink Composition for Organic Light Emitting Devices
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Solution Overview
Problem
Current ink compositions for organic light emitting devices face challenges in achieving high solid content and stable film formation due to low solubility of functional materials and phase separation issues, particularly with solvents having low boiling points that cause nozzle drying in inkjet printing processes.
Innovation Solution
An ink composition comprising solvents represented by specific chemical formulas, which provide high solubility for functional materials and high boiling points, allowing for increased functional material content and stable ink composition, along with a method for manufacturing organic light emitting devices using these solvents to form uniform films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ether-based solvents or hydrocarbon-based solvents with low polarity are used as main solvents, then the ink composition can be discharged stably, but the solubility for functional material is low, leading to long processing time and phase separation during drying
Solution Approach 1:
The patent uses a composite solvent system comprising multiple components: a first solvent (ether-based or hydrocarbon-based with low polarity for discharge stability), a second solvent (aromatic hydrocarbon-based with high solubility for functional materials), and a third solvent (glycol ether-based with high boiling point). This composite approach combines the advantages of each solvent to achieve both stable discharge and homogeneous film formation without phase separation.
Solution Approach 2:
The patent optimizes the boiling point of the solvent mixture to be 100°C or higher by carefully selecting and combining solvents with different boiling points. The third solvent (glycol ether-based) with high boiling point specifically contributes to raising the overall boiling point, preventing nozzle drying while maintaining film formation quality.
2Quantity of substance
If solvents with high solubility for functional material are used, then the amount of functional material that can be dissolved is increased, but the boiling point is low, causing nozzle unit drying in inkjet process
Solution Approach 1:
The patent combines solvents with different boiling points and solubility characteristics. The second solvent (aromatic hydrocarbon-based) provides high solubility for functional materials, while the third solvent (glycol ether-based) with high boiling point compensates for the low boiling point of the second solvent, ensuring the overall mixture has a boiling point of 100°C or higher to prevent nozzle drying.
Solution Approach 2:
The patent specifically controls the boiling point parameter of the solvent mixture to be 100°C or higher by adjusting the composition ratios. The third solvent (glycol ether-based) is specifically selected for its high boiling point property to raise the overall boiling point while maintaining compatibility with the functional materials.
3Manufacturing precision
If the number of drops increased to achieve target thickness due to low solubility, then the thickness can be reached, but the profile becomes non-flat and material consumption increases
Solution Approach 1:
The composite solvent system with optimized solubility characteristics allows higher functional material concentration in the ink. The second solvent (aromatic hydrocarbon-based) specifically enhances solubility, enabling the ink to achieve target film thickness with fewer drops, thereby maintaining profile flatness and reducing material consumption.
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 ink composition enhances the stability and uniformity of the ink, enabling the formation of flat and uniform films with improved solubility and evaporation control, addressing the limitations of existing solvents in achieving target thickness and profile in organic light emitting devices.
Implementation Method 1
an ink composition comprising a solvent comprising a solvent represented by the following Chemical Formula 1, a solvent represented by the following Chemical Formula 2, and a solvent represented by the following Chemical Formula 3; and a charge transferring material or a light emitting material
Implementation Method 2
needs to form a uniform film when forming a film
Implementation Method 3
a solvent used in an ink composition needs to have a high boiling point in order to prevent a problem of a nozzle unit being dried
Data Source
AI summary
The present specification relates to an ink composition comprising a solvent comprising a solvent represented by Chemical Formula 1, a solvent represented by Chemical Formula 2 and a solvent represented by Chemical Formula 3; and a charge transferring material or a light emitting material, and a method for manufacturing an organic light emitting device formed using the ink composition.