Organic EL Upper Electrode Stress Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for forming the upper electrode in organic EL elements, such as the facing target sputtering method, result in low injection performance and high membrane stress, leading to peeling and cracking issues, which reduce the efficiency and lifespan of the organic EL elements.
Innovation Solution
A method involving two film-forming steps for the upper electrode, where the first step uses magnetron sputtering to form a thin film with high adhesion and electron injection properties, followed by a second step using a different method, like facing target sputtering, to reduce membrane stress and prevent peeling and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper electrode is formed by magnetron sputtering method, then excellent electron injection performance is achieved, but high membrane stress causes peeling and cracking
Solution Approach 1:
The upper electrode is divided into multiple thin films formed by different methods. The first thin film is formed by magnetron sputtering to provide excellent electron injection performance, while the second thin film is formed by a different method to provide low membrane stress and prevent peeling and cracking.
Solution Approach 2:
The upper electrode uses a composite structure combining materials and formation methods. By combining the advantages of magnetron sputtering (excellent injection) and other methods (low stress), the composite electrode structure achieves both high reliability and stress resistance.
2Ease of manufacture
If the upper electrode is formed by conventional methods such as facing target sputtering, then manufacturing is easier, but injection performance is low
Solution Approach 1:
The electrode formation process is segmented into multiple steps with different methods. The first step uses magnetron sputtering for excellent injection performance, while subsequent steps use other methods to complete the electrode formation, combining the benefits of different approaches.
Solution Approach 2:
The formation method parameters are changed by combining multiple methods. By changing from a single conventional method to a combination of magnetron sputtering and other methods, both manufacturing feasibility and injection performance are improved.
3Productivity
If high membrane stress is present in the upper electrode, then film formation is simpler, but peeling and cracking occur reducing yield
Solution Approach 1:
The electrode film is segmented into multiple thin films with different stress characteristics. This segmentation allows the overall structure to have reduced membrane stress while maintaining manufacturing efficiency, preventing peeling and cracking.
Solution Approach 2:
The first thin film acts as an intermediary layer that provides excellent electron injection, while the second thin film serves as a stress-management layer. This intermediary structure resolves the conflict between manufacturing simplicity and electrode integrity.
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 approach achieves excellent electron injection and reduced membrane stress, enhancing the efficiency and lifespan of the organic EL elements by minimizing peeling and cracking of the upper electrode.
Implementation Method 1
a first film-forming step of forming a thin film on the organic functional layer by magnetron sputtering
Data Source
AI summary
An organic EL element is provided having a pair of electrodes and an organic functional layer disposed therebetween, the pair of electrodes consisting of an upper electrode and a lower electrode. In the pair of electrodes, the upper electrode includes a first layer and a second layer, the first layer being in contact with the organic functional layer and the second layer being in contact with the first layer. Additionally, the first layer has a higher membrane stress than the organic functional layer and the second layer. Furthermore, the first layer has a crystalline structure and the second layer has a non-crystalline structure.