Organic Electroluminescent Composition With Ultra-Low Zn Impurities
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Solution Overview
Problem
Existing wet film formation methods for organic electroluminescent elements face issues with foreign substance contamination, particularly from zinc (Zn), leading to defects like short circuits and dark spots due to insoluble precipitates formed by Zn reacting with anion components, which are not addressed by existing water-based systems.
Innovation Solution
The composition for organic electroluminescent elements controls the Zn concentration to less than 0.5 ppm, using methods such as acid treatment, ion removal, and careful material purification to maintain a uniform solution, preventing the formation of Zn-caused foreign substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a wet film formation method is used for forming organic thin films, then large-area film formation is facilitated and multiple materials can be mixed in one layer, but foreign substance contamination (particularly Zn) occurs leading to coating defects and short circuits
Solution Approach 1:
The patent applies parameter changes by strictly controlling the Zn concentration parameter to less than 0.5 ppm in the composition. This quantitative parameter control prevents Zn-related foreign substance formation while maintaining the wet film formation method's advantages for large-area manufacturing
Solution Approach 2:
The patent extracts and removes Zn impurities from the composition through purification processes. By taking out the harmful Zn component before film formation, the method prevents coating defects and short circuits while preserving the benefits of wet film formation
2Ease of operation
If organic solvents are used as coating solvents, then film formation is enabled, but salts formed by ionic bonding precipitate as foreign substances causing troubles during film formation
Solution Approach 1:
The patent applies preliminary action by performing purification steps before film formation to remove Zn impurities from the composition. This advance removal prevents Zn salt precipitation during the film formation process, ensuring both operational ease and manufacturing precision
Solution Approach 2:
The patent controls the Zn concentration parameter to less than 0.5 ppm, preventing the formation of insoluble Zn salts that would otherwise precipitate during film formation with organic solvents
3Ease of manufacture
If water-based systems are used for hole injection layer formation, then coating is facilitated, but the amount of metal component mixing in is large (several tens of ppm) causing high contamination levels
Solution Approach 1:
The patent applies parameter changes by reducing the Zn concentration parameter from several tens of ppm in water-based systems to less than 0.5 ppm. This stringent parameter control achieves both ease of manufacture and reduced metal contamination
Solution Approach 2:
The patent extracts Zn impurities from the composition through purification processes, removing the harmful metal components that cause high contamination levels in water-based systems while maintaining coating facilitation
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 ensures uniform film formation, preventing short circuits and dark spots, resulting in organic electroluminescent elements with a longer driving life and improved reliability.
Implementation Method 1
the salt to be formed by ionic bonding is insoluble in the organic solvent, and consequently, a slight amount of an impurity that may not precipitate in a water-based solvent would precipitate as a foreign substance
Data Source
Figure 1
AI summary
The objection of invention is to provide a composition for organic electroluminescent element having a smaller amount of foreign substance. The invention is a composition for organic electroluminescent element, which is for forming at least one layer selected from the group consisting of a light emitting layer, a hole injection layer and a hole transportation layer, wherein the composition comprises an aromatic amine polymer having a weight average molecular weight of 3,000 to 1,000,000 and a solvent, and a Zn concentration in the composition is less than 0.5 ppm.