Solubility-Tunable Hole Transport Polymer for Multilayer Organic EL
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Solution Overview
Problem
Current methods for achieving multilayering in polymer organic electroluminescent (EL) elements face challenges due to solubility issues and water removal difficulties, particularly when using wet processes like printing or inkjet application, which can lead to layer dissolution and require high-temperature or reduced-pressure conditions.
Innovation Solution
A composition comprising a polymer or oligomer with hole transport properties and a thienyl group, combined with an initiator, whose solubility can be altered by heat or light, enabling multilayer formation through coating methods without layer dissolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet processes like printing or inkjet application are used for film formation in polymer organic EL elements, then simple film formation and multilayering are enabled, but the previously formed lower layer dissolves during formation of the upper layer
Solution Approach 1:
The patent applies parameter changes by utilizing solvents with different solubility characteristics for different layers. Specifically, the lower layer is formed using a solvent in which it is soluble, while the upper layer is formed using a solvent in which the lower layer is insoluble. This parameter change in solvent selection enables multilayering without dissolution of previously formed layers, resolving the contradiction between manufacturing simplicity and layer stability.
2Stability of the object's composition
If compounds with significantly different solubility levels are used to achieve multilayering, then layer dissolution is prevented, but water removal becomes problematic requiring high-temperature or reduced-pressure conditions
Solution Approach 1:
The patent changes the solvent parameter from water-based to organic solvent-based systems. By using organic solvents that can be removed under milder conditions compared to water, the patent maintains layer integrity through solubility differentiation while reducing the complexity of processing conditions. The organic solvents allow for easier removal without requiring extreme temperatures or reduced pressures, thus resolving the contradiction between layer stability and processing simplicity.
3Reliability
If high-temperature drying is performed to remove water from the hole injection layer, then water removal is achieved, but preparation of organic EL elements using resin substrates becomes difficult
Solution Approach 1:
The patent changes the solvent parameter from water to organic solvent, which fundamentally alters the drying conditions required. Organic solvents can be removed at lower temperatures compared to water, enabling the use of resin substrates that cannot withstand high-temperature processing. This parameter change resolves the contradiction between effective solvent removal and substrate compatibility by allowing gentle drying conditions suitable for temperature-sensitive resin substrates.
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 allows for effective multilayering of organic layers using a coating method, improving the stability and efficiency of organic EL elements and photoelectric conversion elements by maintaining layer integrity and reducing processing complexities.
Implementation Method 1
a composition comprising a polymer or oligomer (A) having a repeating unit with hole transport properties and also having a thienyl group which may have a substituent, and an initiator (B), wherein a solubility of the composition is capable of being changed by applying heat, light, or both heat and light
Implementation Method 2
a solubility of the composition is capable of being changed by applying heat, light, or both heat and light
Data Source
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Figure 2
AI summary
An embodiment of the present invention relates to a composition containing a polymer or oligomer (A) having a repeating unit with hole transport properties and also having a thienyl group which may have a substituent, and an initiator (B), wherein the solubility of the composition is capable of being changed by applying heat, light, or both heat and light.