Fluorene-Based Compound Crosslinking for OLED Solvent Resistance
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Solution Overview
Problem
Current organic light emitting devices face challenges in achieving high efficiency, low driving voltage, and long service life due to limitations in material stability, charge mobility, and interfacial characteristics, particularly during the solution process, where materials often suffer from solvent resistance and concentration gradients leading to defective devices.
Innovation Solution
A fluorene-based compound with a photocurable or thermosetting group attached to the 9th carbon of the fluorene structure, which forms a stable thin film upon heat or light treatment, reducing steric hindrance and increasing curing group mobility, allowing for a low curing point and improved solvent resistance, enabling the formation of a coating composition for use in organic light emitting devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic materials are used in organic light emitting devices, then the device can be manufactured, but the materials suffer from poor solvent resistance and form concentration gradients during storage, leading to defective devices
Solution Approach 1:
The patent introduces a curing group (such as styrene or ethenyl groups) into the organic material molecule before device assembly. This preliminary modification enables the material to undergo crosslinking reactions after deposition, forming a stable network structure that prevents solvent penetration and concentration gradient formation during storage and operation, thereby resolving the reliability issue.
Solution Approach 2:
The patent creates composite molecular structures by combining conventional organic emitting materials with curing groups (e.g., styrene or ethenyl groups) and fluorine atoms. This composite approach integrates the beneficial properties of each component: the emitting functionality of the organic material, the crosslinking capability of the curing group, and the stability enhancement from fluorine substitution, thereby achieving both high reliability and compositional stability.
2Stability of the object's composition
If materials with high crystallinity are used, then the material structure is stable, but the material is not dissolved well in solutions and crystals form easily, causing concentration gradients and defective devices
Solution Approach 1:
The patent applies local modification by introducing curing groups and fluorine atoms at specific positions within the molecular structure. This localized chemical modification creates regions of high crosslinking density that prevent crystallization and improve solubility, while maintaining the overall structural stability needed for device function, thereby resolving the contradiction between crystallinity and processability.
Solution Approach 2:
The patent changes key molecular parameters by substituting hydrogen atoms with fluorine atoms and incorporating curing groups into the molecular structure. These parameter changes (fluorine substitution, crosslinking capability) fundamentally alter the material's solubility and crystallization behavior, enabling it to form stable solutions without premature crystal formation, thus improving both stability and ease of manufacture.
3Productivity
If the curing group is placed close to the fluorene structure, then the curing reaction is efficient, but steric hindrance increases and curing group mobility decreases
Solution Approach 1:
The patent segments the molecular structure into distinct functional zones: the fluorene core, the linker group, and the curing group. By introducing a linker group (such as alkylene or arylene chains) between the fluorene structure and the curing group, the patent creates spatial separation that reduces steric hindrance and enhances curing group mobility while maintaining efficient curing reaction through proper orbital alignment, thereby resolving the contradiction between reaction efficiency and mobility.
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 fluorene-based compound facilitates the creation of organic light emitting devices with enhanced light emitting efficiency, low driving voltage, and extended service life, while also improving solvent resistance and film retention rates, making it suitable for large-area device implementation.
Implementation Method 1
a fluorene-based compound, which has a curing group, that undergoes crosslinking reaction to form a stable thin film
Implementation Method 2
X1 and X2 are the same as or different from each other, and are each independently a photocurable group or a thermosetting group
Data Source
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Figure 5
AI summary
The present specification relates to a fluorene-based compound of Formula 1, a coating composition comprising the fluorene-based compound of Formula 1, an organic light emitting device using the same, and a manufacturing method thereof.