Organic Electroluminescence Device Layer Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for forming laminated structures in organic electroluminescence devices using wet coating techniques face challenges with charge injection and stability, as polymerization initiators degrade under current, leading to increased driving voltage and reduced brightness stability, shortening the device's lifespan.
Innovation Solution
The method involves forming one layer by polymerizing a polymerizable compound and placing the polymerization initiator in a separate adjacent layer, preventing degradation and maintaining charge injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the polymerization initiator is placed in the same layer as the polymerizable compound, then the organic layer can be formed through polymerization, but the polymerization initiator degrades under current leading to increased driving voltage and reduced brightness stability
Solution Approach 1:
The patent divides the organic electroluminescence device into multiple separate layers: a first organic layer containing the polymerizable compound and a second organic layer containing the polymerization initiator. This segmentation prevents the polymerization initiator from degrading under current in the emitting layer, thereby eliminating harmful degradation products while maintaining the polymerization function for forming solvent-resistant layers.
Solution Approach 2:
The polymerization initiator is extracted from the emitting layer and placed in a separate adjacent layer. This extraction removes the source of harmful degradation products from the functional emitting layer, allowing the emitting layer to maintain stable charge injection and brightness without initiator degradation interference.
2Ease of manufacture
If wet coating method is used to form organic layers, then large-area devices can be manufactured easily, but it is difficult to form laminated structures of three or more organic layers
Solution Approach 1:
The patent applies preliminary polymerization action by forming a solvent-resistant cross-linked polymer layer before subsequent wet coating layers. This preliminary action creates a stable foundation that prevents solvent penetration and layer mixing, enabling successful formation of three or more laminated organic layers through wet coating methods.
Solution Approach 2:
The patent uses composite material strategy by combining polymerizable compounds with cross-linking functionality in the organic layers. This creates solvent-resistant cross-linked polymer networks that maintain layer integrity while allowing multiple layers to be laminated through wet coating, resolving the contradiction between ease of manufacture and laminated structure formation.
3Reliability
If polymerization initiator is used with polymerizable compound in the same layer, then organic layer formation is achieved, but charge injection and charge movement are inhibited by initiator degradation products
Solution Approach 1:
The patent segments the device structure into distinct layers: the emitting layer containing polymerizable compounds for charge transport and the adjacent layer containing polymerization initiator. This segmentation prevents initiator degradation products from forming in the emitting layer, maintaining charge injection efficiency while still enabling polymerization for solvent resistance in the non-emitting layer.
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 enhances the driving lifetime and chemical stability of organic electroluminescence devices by isolating the polymerization initiator from the emitting layer, reducing voltage rise and brightness degradation during energization.
Implementation Method 1
an organic layer is formed through polymerization reaction of a film formed from a solution that contains a diamine compound having epoxy group
Implementation Method 2
electroluminescence devices that uses organic thin films (organic electroluminescence devices)
Data Source
Figure 1~3
AI summary
To provide an organic electroluminescence device that can suppress rise in the driving voltage at the time of constant-current energization and degradation in brightness at the time of energization, and thus excels in its driving lifetime, the organic electroluminescence device comprises: a substrate; an anode and a cathode overlying the substrate; and a plurality of organic layers disposed between the anode and the cathode, and the plurality of organic layers comprise at least: a first layer formed by means of polymerization of a polymerizable compound; and a second layer disposed adjacently to the first layer and containing a polymerization initiator.