Cross-Linking Polymer Composition for Stable Organic EL Films
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Solution Overview
Problem
Conventional methods for forming organic electroluminescent elements using the wet deposition method face challenges in achieving high operation stability due to difficulties in lamination and the inability to control the number of cross-linking groups, leading to unreacted groups that affect device performance.
Innovation Solution
A composition containing at least two cross-linking compounds with different average numbers of cross-linking groups is used, each having a hole-transporting site and constitutional repeating units, to control the number of cross-linking groups and improve polymer film stability, thereby enhancing the operation stability of organic electroluminescent elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the wet deposition method is used to form organic layers, then the need for vacuum process is eliminated and large deposition area is achieved, but operation stability deteriorates due to difficulty in lamination
Solution Approach 1:
The invention changes the chemical parameter of the polymer by introducing cross-linking groups with specific average numbers (0.5-2.0 per repeating unit). This parameter change enables the polymer to form stable cross-linked structures that improve operation stability while maintaining wet deposition advantages
Solution Approach 2:
The invention uses composite materials by combining cross-linking compounds with specific functional groups (triarylamine, carbazole, etc.) and cross-linking groups in a single polymer structure. This composite approach enables both easy deposition and high operation stability
2Device complexity
If a single cross-linking compound is used in wet deposition, then the deposition process is simple, but operation stability deteriorates due to unreacted cross-linking groups
Solution Approach 1:
The invention optimizes the average number of cross-linking groups to be 0.5-2.0 per constitutional repeating unit, which ensures sufficient cross-linking for stability while preventing excessive cross-linking that would cause unreacted groups and device degradation
Solution Approach 2:
The invention introduces different types of cross-linking groups at different locations within the polymer structure (in constitutional repeating units and/or in portions other than constitutional repeating units), creating local variations in cross-linking density that improve overall device stability
3Stability of the object's composition
If cross-linking groups are introduced to improve film stability, then polymer film stability is improved, but device performance deteriorates due to unreacted cross-linking groups
Solution Approach 1:
The invention precisely controls the average number of cross-linking groups to be 0.5-2.0 per constitutional repeating unit, which optimizes the balance between film stability and device performance by ensuring complete reaction of cross-linking groups without excessive cross-linking
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 use of the composition with controlled cross-linking groups results in a highly stable polymer film, improving the operation stability of organic electroluminescent elements and enabling their application in various devices such as flat-panel displays and solar cells.
Implementation Method 1
polymerizing the cross-linking compounds
Data Source
Figure 1
AI summary
The present invention relates to a composition for use in an organic device, comprising at least two cross-linking compounds, wherein each of the at least two cross-linking compounds is a polymer that has a hole-transporting site and constitutional repeating units, the at least two polymers having different average numbers of cross-linking groups per constitutional repeating unit and/or different numbers of cross-linking groups in portions other than the constitutional repeating units, and wherein the cross-linking compounds are compounds having a partial structure of the following formula [109]: The present invention further pertains to an organic electroluminescent element that comprises an anode and a cathode on a substrate and at least one organic layer disposed between the anode and the cathode, wherein at least one organic layer is a layer that is produced by forming a film of the composition for use in an organic device above.